IT 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

LOS  ANGELES 


THE  OPHTHALMOSCOPE 

AND 

HOW  TO    USE    IT 


THORINGTON 


BY  THE  SAME  AUTHOR 


Refraction  and  How  to  Refract 

Third  Edition.     With  215  Illustrations,   many  of 
which  are  from  original  drawings,  seven  being  colored. 

Cloth,  net,  $J.50. 

From.  The  New  York  Medical  Record: 

"Can  be  recommended  not  only  to  beginners  in  the  study 
of  ophthalmology,  but  to  those  practitioners  and  students  as 
well  whose  limited  knowledge  of  mathematics  precludes  the 
study  of  Helmholtz  or  Donders. ' ' 


Retinoscopy  (The  Shadow  Test) 

In  the  Determination  of  Refraction  at  One    Meter 
Distance  with  the  Plane  Mirror. 

Fourth   Edition.       51   Illustrations,  a   number    of 
which  are  in  colors.  Cloth,  net,  $J.OO. 


THE  OPHTHALMOSCOPE 

AND 

HOW  TO  USE  IT 


WITH    COLORED  ILLUSTRATIONS,  DESCRIPTIONS,  AND 

TREATMENT  OF  THE   PRINCIPAL   DISEASES 

OF  THE  FUNDUS 


JAMES   THORINGTON,  A.M.,  M.D. 

AUTHOR   OF  "REFRACTION  AND  HOW  TO   REFRACT"  (THIRD  EDITION)  AND  "RETINOS- 
COPY"  (FOURTH  EDITION);   PROFESSOR  OF  DISEASES  OF  THE  EYE  IN  THE  PHILA- 
DELPHIA POLYCLINIC   AND   COLLEGE  FOR   GRADUATES  IN   MEDICINE;    MEMBER 
OF   THE  AMERICAN   OPHTHALMOLOGICAL  SOCIETY;     FELLOW   OF 
THE   COLLEGE   OP   PHYSICIANS;     ETC. 


73  illustrations  — 12  Colored  plates 


PHILADELPHIA 
P.    BLAKISTON'S   SON   &   CO. 

IOI2    WALNUT    STREET 
1906 


COPYRIGHT,  1906,  BY  P.  BLAKISTON'S  SON  &  Co. 


PRESS  OF 

THE  NEW  ERA  PRINTKG& 
LAHCASTER.  PA, 


PREFACE. 


THIS  book  has  been  written  for  the  student  and 
general  practitioner  who  desires  to  obtain  a  work- 
ing knowledge  of  the  ophthalmoscope  with  the  in- 
terpretations of  its  findings,  and  has  not  the  time, 
ordinarily,  to  study  a  large  text-book  on  the  dis- 
eases of  the  eye,  in  which  the  subject  is  too  deeply 
embedded  for  immediate  comprehension. 

While  it  is  admitted  by  every  intelligent  practi- 
tioner that  the  ophthalmoscope  for  the  detection 
of  many  diseases  is  frequently  a  necessity,  yet  to 
be  able  to  use  the  instrument  does  not  mean  that 
the  observer  must  be  an  expert  ophthalmologist. 

With  the  ophthalmoscope,  the  examiner  may 
see  conditions  pictured  which  signify  disease  of  the 
brain,  spinal  cord,  heart,  kidney,  blood,  blood- 
vessels, etc.,  that  he  might  not  detect  in  any  other 
way,  thus  making  a  diagnosis  with  certainty  and 
satisfaction. 

In  the  preparation  of  the  manuscript  and  the 
arrangement  of  these  pages  and  chapters,  the 
writer  has  planned  to  be  systematic  and  practical, 
so  that  starting  with  the  consideration  of  the  oph- 
thalmoscope and  its  optic  principles  as  also  the 
optic  principles  and  anatomy  of  the  eye,  the  reader 
is  brought  to  a  knowledge  of  the  normal  eye  and 


VI  PREFACE. 

has  a  colored  sketch  presented  of  a  healthy  eye 
ground  as  a  guide  for  comparative  descriptions. 
Finally  the  reader  is  given  a  comparison  of  the 
normal  with  the  pathologic,  so  that  when  he  sees 
a  certain  condition  in  the  eye  ground,  he  will  know 
at  once  whether  the  appearance  indicates  health, 
or  an  anomaly  or  disease,  and  the  structure  or 
structures  involved.  However,  to  enhance  the 
value  of  the  work,  the  writer  has  selected  for  his 
descriptions  and  illustrations  those  diseases  of  the 
eye  ground  which  appeal  to  the  general  practitioner 
in  every-day  practice.  The  sketches  in  color  were 
made  by  a  noted  artist  and  under  the  writer's  per- 
sonal supervision,  from  individual  patients  in  his 
own  practice.  These  sketches,  made  by  the  aid  of 
artificial  light,  should  be  studied  under  similar  con- 
ditions (see  page  in). 

The  subject  of  prognosis  and  treatment  of  the 
various  diseases  described  has  not  been  exhausted, 
but  has  been  sufficiently  touched  upon  to  give  the 
reader  a  proper  understanding  of  the  subject  with- 
out making  a  work  of  this  character  unnecessarily 
large. 

120  S.  EIGHTEENTH  ST.,  PHILADELPHIA,  PA. 
January,  1906. 


CONTENTS. 


CHAPTER    I. 

THE  OPHTHALMOSCOPE.— CHOICE  OF  AN  OPH- 
THALMOSCOPE. —  VARIETIES.  —  ILLUMINATION.  - 
THE  MIRROR.  — MYDRIATICS.— OBSERVER.  — PA- 
TIENT.—HOW  TO  USE  THE  OPHTHALMOSCOPE.— 
DIRECT  AND  INDIRECT  METHODS.  OBLIQUE  IL- 
LUMINATION    i 

CHAPTER    II. 

OPTICS.— LIGHT.— REFLECTION.— R  EFRACTION.— 
LENSES.— HYPERMETROPIA.— MYOPIA.— ASTIGMA- 
TISM.—ESTIMATING  THE  REFRACTION  BY  THE 
DIRECT  AND  INDIRECT  METHODS  AND  RETINO- 
SCOPY 44 

CHAPTER    III. 

ANATOMY  AND  ANOMALIES  OF  THE  EYE. 79 

CHAPTER    IV. 

THE  NORMAL  EYE  GROUND 108 

CHAPTER   V. 

STRUCTURAL  ALTERATIONS  OR  CHANGES  IN  THE 
CORNEA,  AQUEOUS  HUMOR,  IRIS,  LENS  AND 
VITREOUS  HUMOR  WHICH  ARE  INDICATIVE  OF 
DISEASE  OR  INJURY 128 

vii 


Vlll  CONTENTS. 

CHAPTER    VI. 

VISUAL  ACUITY.— FIELD  OF  VISION.— PERIMETRY. ..   140 

CHAPTER    VII. 

RETINAL  VESSELS.  —  HEMORRHAGES.  —  PIGMENT.  — 
CHANGES.— HYPEREMIA.— ANEMIA.— EMBOLISM.— 
THROMBOSIS  148 

CHAPTER   VIII. 

DISEASES  OF  THE  RETINA 176 

CHAPTER    IX. 

DISEASES  OF  THE  OPTIC  NERVE 229 

CHAPTER    X. 

DISEASES  OF  THE  CHOROID.— GLAUCOMA 259 

INDEX 287 


LIST  OF  ILLUSTRATIONS. 


PLATES 

PACE. 

I.  Normal  Fundus To  face  1 18 

II.  Embolism  of  the  Central  Artery "  164 

III.  Thrombosis    of   the    Central    Vein    (So- 

called  Hemorrhagic  Retinitis) "  172 

IV.  Albuminuric  Retinitis "  190 

V.  Albuminuric  Retinitis  of  Pregnancy....       "  198 

VI.  Retinitis  Diabetica "  202 

VII.  Retinitis  Pigmentosa "  208 

VIII.  Detachment  of  the  Retina "  216 

IX.  Atrophy  of  the  Optic  Nerve  (Post  Pap- 
illitic  Atrophy)  also  Medullated  Nerve- 
fibers  "  248 

X.  Primary  Optic  Atrophy "  252 

XI.  Retino-Choroiditis    "  264 

XII.  Glaucoma  "  278 

TEXT    FIGURES. 

1.  The  Loring  Ophthalmoscope 3 

2.  The  Morton  Ophthalmoscope 5 

3  and  4.  The  DeZeng  Luminous  Ophthalmoscope...  7 

5.  The  Student  Lamp  and  Cover  Chimney  with  Ad- 

justable Bracket 10 

6.  Author's  Iris  Diaphragm  Chimney n 

7.  Author's  Schematic  Eye 14 

8.  Correct  Position  for  Direct  Ophthalmoscopy 23 

9.  Correct  Position  for  Holding  the  Ophthalmoscope.  24 

ix 


X  LIST    OF    ILLUSTRATIONS. 

PAGE. 

10.  Very  Faulty  Position  of  Holding  the  Ophthalmo- 

scope      25 

11.  Direct  Ophthalmoscopy,  Outlined  in  Hypermetropia  28 

12.  Direct  Ophthalmoscopy,  Outlined  in  Myopia 29 

13.  Position  for  Indirect  Ophthalmoscopy 30 

14.  Author's  Condensing  Lens 31 

15.  Indirect  Ophthalmoscopy,  Outlined 33 

1 6.  Oblique  or  Focal  Illumination 38 

17.  Oblique  or  Focal  Illumination  and  Object  Magni- 

fied with  Condensing  Lens , 39 

18.  Loupe    40 

19.  Oblique  or  Focal  Illumination  with  Object  Magni- 

fied with  Loupe 41 

20.  Cover  Chimney  with  Condensing  Lens  Attached.  . .  42 

21.  Illustrating  Intensity  of  Light 45 

22.  Parallel  Rays  Refracted  by  a  Convex  Lens  Form- 

ing a  Convergent  Pencil 46 

23.  Parallel  Rays  Reflected  by  a  Concave  Mirror  Form- 

ing a  Convergent  Pencil 46 

24.  Illustrating  a  Divergent  Pencil 48 

25.  Reflection    50 

26.  Reflection  from  a  Plane  Mirror 51 

27.  Lateral  Inversion 52 

28.  Reflection  by  a  Concave  Mirror 54 

29.  Erect  Image  Formed  by  a  Concave  Mirror 54 

30.  Inverted  Image  Formed  by  a  Concave  Mirror 55 

31.  Image  Formed  by  a  Convex  Mirror 56 

32.  Perpendicular  to  Plane  Surfaces 58 

33.  Refraction  58 

34.  Maximum  Deviation 59 

35.  Minimum  Deviation   59 

36.  37,  and  38.  Convex  Lenses 60 

39,  40,  and  41.  Concave  Lenses 61 

42.  Prism  Formation  of  a  Convex  Lens 62 

43.  Prism  Formation  of  a  Concave  Lens 62 


LIST    OF    ILLUSTRATIONS.  XI 

PAGE. 

44.  Parallel  Rays  Passing  Through  a  Convex  Lens.  . .  63 

45.  Parallel  Rays  Passing  Through  a  Concave  Lens ...  63 

46.  Conjugate  Foci   64 

47.  Negative  Focus 65 

48.  Inverted  Image  Formed  by  a  Convex  Lens 65 

49.  Erect  and  Magnified  Image  Formed  by  a  Convex 

Lens 66 

50.  Image  Formed  by  a  Concave  Lens 66 

51  and  52.  Convex  and  Concave  Cylinder  Lenses 68 

53.  Cylinder  Axis 69 

54.  Parallel  Rays  Passing  Through  a  Convex  Cylinder.  69 

55.  Parallel  Rays  Passing  Through  a  Concave  Cylinder.  70 

56.  Hypermetropic  Eye  at  Rest 70 

57.  Hypermetropic  Eye  Refracted 71 

58.  Emmetropia    71 

59.  Myopic  Eye  at  Rest 71 

60.  Myopic  Eye  Refracted 72 

61.  Horizontal  Section  of  the  Right  Eye 80 

62.  Varieties  of  Persistent  Pupillary  Membrane 101 

63.  Various  Forms  of  Opacity  of  the  Crystalline  Lens.  .  102 

64.  Head  of  the  Optic  Nerve no 

65.  To  Determine  the  Position  of  a  Fixed  Opacity  in 

the  Eye 138 

66.  Randall's  Test  Letters 140 

67.  Gould's  Test  Letters 141 

68.  Illiterate  Card   142 

69.  McHardy's    Perimeter 143 

70.  Field  Charts 144 

71.  Form  Field  Showing  Contraction  in  All  Meridians.  212 

72.  Form  Field  in  Partial  Detachment  of  the  Retina.  .  .  220 

73.  Depressions  in  Optic  Disc 233 


THE   OPHTHALMOSCOPE 

AND 

HOW  TO  USE  IT 


CHAPTER    I. 

THE  OPHTHALMOSCOPE.  CHOICE  OF  AN  OPHTHALMOSCOPE. 
VARIETIES.  ILLUMINATION.  THE  MIRROR.  MYDRIATICS. 
OBSERVER.  PATIENT.  HOW  TO  USE  THE  OPHTHALMO- 
SCOPE. DIRECT  AND  INDIRECT  METHODS.  OBLIQUE 
ILLUMINATION. 

Ophthalmoscope.  From  o<£0aX/xos,  "  eye  ";  and 
ayoTreiv,  "  to  observe  "  or  literally  "  to  view  an  eye." 
An  instrument  used  for  studying  the  media  and 
interior  of  an  eye. 

Choice  of  an  Ophthalmoscope.  As  the  purpose 
of  an  ophthalmoscope  is  to  permit  the  observer  to 
see  clearly  the  interior  of  an  eye,  therefore  in  select- 
ing an  ophthalmoscope  it  is  not  at  all  necessary  to 
obtain  the  most  expensive  or  most  complicated  in- 
strument, but  rather  to  select  the  one  which  will 
answer  the  purpose  for  which  it  is  intended.  The 
original  ophthalmoscope  of  Helmholtz  (1851)  is 
a  crude  affair  and  is  now  a  museum  curiosity,  as 
the  ophthalmoscope  of  the  present  day  excels  the 


2  THE    OPHTHALMOSCOPE. 

Helmholtz  instrument  in  every  particular.  There 
is  an  infinite  variety  of  ophthalmoscopes  in  the 
market,  but  for  the  general  student  the  modified 
instrument  of  Loring  appears  to  meet  with  most 
favor  in  America,  and  the  Morton,  an  excellent  in- 
strument, is  quite  popular  abroad. 

The  Loring  Ophthalmoscope  (Fig.  i).  The 
mirror  of  the  Loring  instrument  is  concave,  with 
a  radius  of  curvature  of  40  centimeters,  giving 
therefore  a  principal  focus  at  20  centimeters.  The 
sight-hole  of  this  mirror  is  round  and  usually  about 
3^2  millimeters  in  diameter,  cut  through  the  glass. 
As  an  improvement  over  such  a  mirror  and  to  take 
its  place,  the  writer  would  recommend  the  mirror 
used  on  his  own  ophthalmoscope  which  has  a  radius 
of  curvature  of  15  centimeters  and  the  sight-hole 
2  millimeters  in  diameter,  not  cut  through  the  glass, 
but  made  by  simply  removing  the  quicksilver.  The 
glass  left  at  the  sight-hole  gives  additional  reflect- 
ing surface  and  at  the  same  time  does  away  with 
annoying  reflexes  or  aberrations  which  often  oc- 
cur when  the  glass  is  perforated.  The  small  sight- 
hole  is  an  advantage  also  when  looking  through 
small  pupils.  The  mirror  should  be  of  thin  glass 
and  the  silvering  of  the  very  best  quality.  The 
mirror  can  be  tilted  to  an  angle  of  25  degrees,  is 
oblong  in  shape,  18  by  33  millimeters,  and  is  se- 
cured at  the  middle  of  its  ends  (Fig.  i)  by  two 
elevated  screws  to  the  cover  on  a  revolving  milled 
wheel.  This  milled  wheel  or  disk  contains  fifteen 


THE    LORING    OPHTHALMOSCOPE.  3 

small  spheric  lenses,  each  6  millimeters  in  diameter, 
set  in  the  form  of  a  circle  near  its  circumference. 
The  series  of  spheric  lenses  of  different  strength 
range  from  —  I  D.  to  —  8  D.  and  from  +  i  D.  to 


FRONT  BACK 

FIG.  i. — Loring  Ophthalmoscope. 


+  7  D.  The  central  opening  is  left  free,  does  not 
contain  a  lens  and  is  marked  o.  Each  lens  may  be 
turned  in  succession  to  the  sight-hole  by  revolving 
the  milled  wheel  or  disk  with  the  end  of  the  index 


4  THE   OPHTHALMOSCOPE. 

finger  of  the  hand  which  holds  the  instrument  ( Fig. 
10).  When  it  is  necessary  to  use  a  lens  stronger 
than  —  8  D.  or  -f-  7  D.,  there  is  an  additional  quad- 
rant ("back"  view,  Fig.  i),  which  can  be  super- 
imposed and  turned  into  place  at  the  sight-hole; 
this  quadrant  contains  four  lenses,  — 0.50  D.  and 
—  16  D.;  also  +  0.50  D.  and  +  16  D.  With  this 
quadrant  and  the  spheres  in  the  milled  wheel  any 
combination  or  strength  of  lens  from  — 0.50  D.  to 
-24  D.  and  +0.50  D.  to  +23  D.  (a  series  of 
sixty- four)  may  be  placed  at  the  sight-hole,  as 
shown  by  the  following  table. 

Plus.  Mill  us. 

0  I 

1  2 

2  3 

3  4 

4  5 

5  6 

6  7 

7  8 
Bring  up  +  16  Bring  up  —  16 

+  i6C  —  8=   8                                  —  i6C  +  7=  9 

—  7=9  +6=  10 

—  6=10  +5=  ii 

—  5  =  ii  +4=  12 

—  4=12  +3=  13 

—  3=i3  +2=  14 

—  2=14  +1=  15 

—  i  =  15  +0=  16 

—  0=16  —i=  17 
+  1  =  17  —2=  18 
+  2=18  —3=  19 
-(-3=19  —  4  =  20 
+  4  =  20  — 5=  21 
-(-5  =  21  — 6=  22 
+  6  =  22  —  7  =  23 


THE    MORTON    OPHTHALMOSCOPE. 


Plus. 


Bring  up  -f-  0.50 


C  +  i  = 


0.50 

1-50 

2.50 

3-50 
4-50 
5-50 
6.50 
7-50 


Bring  up  — 0.50 


Minus. 

—  8  =    24 

=  —  0.50 
:  — 1  =  — 1.50 
:  —  2  =  —  2.50 
: — 3  = — 3-50 

—  4  =  —  4.50 

:  —  s  =  —  5-50 
:— 6=1  —  6.50 
:  —  7  =  —  7-50 

—  8  =  —  8.50 


An  index  immediately  beneath  the  sight-hole  of 
the  instrument  records  the  strength  of  lens  in  whole 
numbers  that  is  being  used.  In  the  Morton  instru- 
ment each  lens  is  projected  before  the  sight-hole 


FIG.  2. — Morton  Ophthalmoscope. 

through  an  endless  groove  and  propelled  by  a  driv- 
ing wheel  and  cogs  at  the  lower  end  of  the  instru- 
ment (Fig.  2).  In  this  Loring  instrument  the 


6  THE    OPHTHALMOSCOPE. 

minus  lenses  are  numbered  in  red  figures  and  the 
plus  lenses  in  white.  The  Morton  uses  the  reverse 
of  these  colors,  i.  e.,  white  for  the  minus  lenses  and 
red  for  the  plus.  When  the  0.50  lens  (plus  or  mi- 
nus) is  in  position  then  its  strength  must  be  added 
to  or  subtracted  from  the  whole  number  at  the 
sight-hole.  By  the  foregoing  table  it  will  be  noted 
that  —  8.50  and  +  7.50  are  the  highest  half-num- 
bers that  can  be  obtained  or  are  ever  necessary  for 
any  purpose.  The  handle  of  either  ophthalmoscope 
is  made  partly  of  brass  and  partly  of  bone;  this 
latter  can  be  unscrewed  when  the  instrument  is  to 
be  placed  in  its  case.  In  the  case  with  the  ophthal- 
moscope there  is  a  convex  lens  of  +  16  D.,  which 
will  be  described  later. 

The  Luminous  Ophthalmoscope  (Figs.  3  and 
4),  DeZeng  Patent.  This  instrument  is  the  Lor- 
ing  ophthalmoscope  just  described  with  the  addi- 
tion of  an  electric  light  attachment  and  a  mirror  of 
different  size  and  shape.  This  mirror  is  plain,  cir- 
cular in  form,  14  millimeters  in  diameter,  with  one 
millimeter  of  its  upper  area  cut  away  horizontally. 
The  flat  top  edge  of  the  mirror  is  on  a  level  with  the 
lower  edge  of  the  sight-hole  in  the  ophthalmoscope ; 
this  mirror  is  placed  at  an  angle  of  43  degrees  and 
firmly  secured  to  the  instrument  as  it  is  never  neces- 
sary to  tilt  it.  The  observer  in  looking  through  the 
sight-hole  always  looks  over  the  mirror  and  never 
through  it.  The  handle  of  the  instrument  is  hollow 
and  carries  the  electric  wires  to  a  small  5-volt  lamp 


THE    LUMINOUS    OPHTHALMOSCOPE. 


in  the  handle.    Between  the  lamp  and  the  mirror  is 
placed  a  very  strong  planoconvex  lens.     The  rays 


FIG.  3.  FIG.  4. 

DeZeng   Luminous   Ophthalmoscope.     Two-thirds   size. 

of  light  from  the  filament  falling  upon  the  convex 
lens  are  refracted  very  convergently  and  after  re- 


8  THE   OPHTHALMOSCOPE. 

flection  from  the  mirror  converge  to  a  point  one 
inch  distant  (Fig.  4).  The  luminous  ophthalmo- 
scope is  so  convenient  for  use  in  the  wards  of 
a  hospital,  etc.,  and  renders  ophthalmoscopy  so 
much  less  difficult  that  the  instrument  at  once  com- 
mends itself  to  every  physician.  This  instrument 
is  ideal  both  for  the  direct  and  indirect  method, 
and  has  the  following  points  of  merit :  The  mirror 
and  light  are  stationary,  thus  giving  the  observer 
any  liberty  of  movement  necessary  without  any  loss 
of  the  reflection  from  the  mirror,  the  mirror  never 
requires  any  tilting,  the  brilliancy  or  intensity  of  the 
illumination  at  the  fundus  by  virtue  of  the  light 
being  so  close  to  the  mirror  far  exceeds  that  of  the 
non-luminous  instrument,  and  for  the  same  reason 
the  size  of  the  retinal  illumination  is  made  about 
five  times  larger  than  that  by  the  old  style  instru- 
ment. The  heat  from  the  electric  lamp  is  infinitesi- 
mal. An  electric  light  attachment  is  also  made  for 
the  Morton  ophthalmoscope. 

Electricity  to  supply  the  luminous  ophthalmo- 
scope may  be  furnished  by  a  portable,  storage,  or 
dry  cell  battery  or  by  the  Edison  street  current. 
No  matter  what  the  supply  may  be,  there  should 
always  be  a  convenient  rheostat  attacluncnt  at  liand 
so  that  the  operator  may  know  that  he  is  not  using 
more  current  than  the  delicate  lamp  can  possibly 
endure. 

The  Thorner  Ophthalmoscope  is  a  large  sta- 
tionary instrument  and  an  expensive  one.  It  is 


HOW    TO    USE   THE   OPHTHALMOSCOPE.  9 

used  principally  for  magnification  and  class  demon- 
stration and  is  therefore  not  a  part  of  the  subject 
matter  of  this  manual. 

How  to  Use  the  Ophthalmoscope.  While  the 
beginner  in  ophthalmoscopy  may  see  into  an  eye 
the  first  time  he  makes  the  attempt,  yet  proficiency 
with  the  use  of  the  ophthalmoscope  does  not  come 
except  by  long  and  constant  practice.  The  pupil 
of  an  eye  in  health  appears  to  an  observer  as  black 
(the  eye  of  an  albino  excepted) ;  this  is  due  to  the 
fact  that  the  observer's  eye  does  not  ordinarily  in- 
tercept any  of  the  rays  of  light  which  return  from 
the  eye.  Rays  of  light  entering  an  eye  are  returned 
by  that  eye  toward  their  immediate  source  and 
therefore,  if  an  observer  wishes  to  see  into  or 
study  the  interior  of  an  eye,  he  must  have  his  own 
eye  in  the  path  of  the  returning  rays.  To  accom- 
plish this,  the  observer  places  a  mirror  in  front  of 
his  eye  and  reflects  light  into  the  pupil  of  another 
eye,  and  as  the  rays  return  from  the  eye  under  ob- 
servation, to  the  mirror  from  which  they  came,  the 
observer  is  able  to  receive  some  of  these  return 
rays  into  his  own  eye  through  a  small  opening 
which  has  been  previously  made  in  the  mirror. 

Several  important  matters  should  receive  very 
careful  attention  from  the  student  or  beginner  be- 
fore he  attempts  to  use  the  ophthalmoscope,  and 
these  points  will  be  taken  up  seriatim. 

The  Room.  This  should  be  darkened  by  draw- 
ing the  shades  or  closing  the  blinds,  the  darker 


10 


THE    OPHTHALMOSCOPE. 


the  room  the  better,  though  it  is  not  at  all  necessary 
to  have  the  walls  painted  black  or  draped  in  black 
cloth.  All  lights  except  the  one  in  use  should,  if 
possible,  be  excluded  from  the  dark  room.  If  the 
surgeon  has  a  convenient  room  adjoining  his  office 
and  so  desires,  he  may  have  it  fitted  up  as  a  "  dark 
room  "  by  having  the  walls  and  ceiling  painted 
black  or  draped  in  black  felt,  as  just  suggested. 

The  Light.  A  candle  flame  is  almost  useless 
as  it  is  not  steady  and  moves  with  each  current  of 
air.  Gas  is  the  most  common  and  convenient  illumi- 


FIG.  5.  Student  lamp  with   cover   chimney,   on   adjustable  bracket. 

nant,  as  nearly  every  house,  even  in  the  smallest 
city,  is  piped  for  the  purpose,  and  with  rubber 
tubing  this  may  be  brought  to  any  adjustable  stand. 
A  good  quality  of  kerosene,  in  a  modern  lamp,  may 
be  used  if  gas  cannot  be  had.  The  student  lamp  is 
good,  but  the  flame  is  rather  narrow.  The  student 
lamp  on  a  bracket  is  good  if  the  cover  chimney 


THE    LIGHT. 


I  I 


is  used  ( Fig.  5  ) .  To  use  daylight  it  would  be  nec- 
essary to  have  a  round  opening  il/2  inches  in  di- 
ameter in  the  closed  blind  or  drawn  shade,  and  this 
opening  would  have  to  be  exactly  placed  to  meet 
the  conveniences  of  the  office  furniture.  But  day- 
light is  an  uncertain  quantity  and  cannot  be  relied 
upon.  There  is  one  thing  in  favor  of  daylight  how- 
ever, and  that  is  we  can  see 
the  eye  ground  in  its  natural 
coloring  and  not  altered  by 
the  yellow  coloring  from  the 
reflected  gas  or  lamp  light. 
The  regular  i6-candle-power 
electric  light  with  its  narrozv 
filament  is  somewhat  objec- 
tionable, though  some  obser- 
vers use  it,  preferably  with  a 
ground  glass  bulb  or  the  coiled 
filament.  There  is  no  objec- 
tion to  the  Welsbach  light  if 
the  mantle  is  intact.  What- 
ever variety  of  light  is  used  it 
should  have  the  qualifications 
of  being  steady  and  bright, 
a  white  light  if  possible.  The  Argand  burner  is 
the  most  generally  employed  and  most  satisfactory 
when  on  a  convenient  right-angled  bracket  ( Fig.  5  ) 
which  can  be  raised  or  lowered,  and  is  capable  of 
lateral  movement.  The  flame  or  electric  light  may 
be  exposed  or  covered  with  the  iris  diaphragm 


FIG.  6. — Author's  Iris  Dia- 
phragm Chimney. 


12  THE   OPHTHALMOSCOPE. 

chimney  (Fig.  6).  If  the  luminous  ophthalmoscope 
is  used,  the  question  of  light  is  settled  at  once,  as 
the  filament  gives  a  point  of  light  which  is  perfect. 
And  furthermore,  the  light  and  mirror  of  this  in- 
strument being  two  fixed  points,  the  observer  has 
no  trouble  in  keeping  his  light  in  position  for  reflec- 
tion and  does  not  have  to  tilt  his  mirror,  and  for 
bedside  work  the  observer  can  follow  the  eye  of  the 
most  restless  patient  without  losing  the  reflection. 

Reflection  from  the  Mirror.  It  has  already 
been  stated  that  the  concave  mirror  on  the  ophthal- 
moscope has  a  radius  of  curvature  of  40  centi- 
meters (16  inches)  and  this  means  that  if  the  light 
is  placed  20  centimeters  (8  inches)  from  the  mirror, 
the  rays  of  light  would  be  reflected  parallel.  This 
should  be  borne  in  mind  for  occasionally  parallel 
rays  are  required  and  this  is  a  good  way  to  obtain 
them,  and  if  divergent  rays  are  required  the  light 
must  be  placed  at  six  or  seven  inches.  If  the 
light  is  just  40  centimeters  from  the  mirror,  then 
the  reflected  rays  would  have  a  convergence  of 
40  centimeters,  as  this  distance  represents  the  cen- 
ter of  curvature  (c.c.  in  Fig.  29). 

To  summarize: 

1.  To  obtain  parallel  rays  of  light  reflected  from 
the  mirror,  place  the  light  20  centimeters  distant. 

2.  To  obtain  divergent  rays  of  light  reflected 
from  the  mirror,  place  the  light  closer  than  20 
centimeters. 

3.  To  obtain  convergent  rays  of  light  reflected 


MOVEMENT    OF   THE    MIRROR.  13 

from  the  mirror,  place  the  light  beyond  20  centi- 
meters. The  further  the  light  is  beyond  20  centi- 
meters from  the  mirror,  the  greater  the  conver- 
gence. 

For  most  ophthalmoscopic  work  convergent  rays 
are  employed,  but  when  studying  minute  changes 
in  the  retina,  nerve-head,  vitreous,  etc.,  a  faint 
light  is  sometimes  required,  and  at  other  times  in 
studying  gross  changes,  the  brightest  or  most  in- 
tense light  obtainable  is  necessary ;  the  former  may 
be  obtained  by  reducing  the  size  of  the  flame  in  use, 
or  substituting  a  plane  mirror.  With  the  luminous 
ophthalmoscope  and  a  convenient  rheostat  a  very 
intense  light,  or  one  of  moderate  strength,  may  be 
obtained.  A  concave  mirror  gives  a  more  brilliant 
illumination  than  a  plane  mirror,  and  each  has  its 
particular  advantages,  as  in  certain  instances,  just 
referred  to;  and  mirrors  with  different  radii  of 
curvature  could  be  used  to  advantage,  but  too  many 
mirrors  are  an  inconvenience.  The  Morton  oph- 
thalmoscope has  a  concave  and  also  a  plane  mirror 
which  may  be  used  independently.  Light  from  the 
concave  mirror  usually  falls  as  a  converging  cone 
of  light,  and  the  base  of  the  cone  is  the  mirror,  but 
when  examining  an  eye  by  the  direct  method  (Fig. 
8)  then  only  those  rays  around  the  sight-hole  of 
the  mirror  enter  the  patient's  pupil. 

Movement  of  the  Mirror.  The  mirror  must 
always  be  tilted  toward  the  light.  When  looking 
into  the  eye  from  a  short  distance  and  before  be- 


THE   OPHTHALMOSCOPE. 


ginning  a  study  of  the  fundus  of  the  eye,  it  is  well 
to  reflect  the  light  into  the  eye  by  moving  or  rotat- 
ing the  handle  of  the  ophthalmoscope,  so  that  the 
light  passes  through  the  different  meridians,  hori- 


FIG.    7. — The   Author's   Schematic    Eye. 

zontally,  vertically  and  diagonally,  and  in  this  way 
opacities  and  the  character  of  the  refraction  of  the 
eye,  may  be  promptly  recognized.  These  conditions 
will  be  referred  to  elsewhere  in  the  text. 

Schematic  Eye  (Fig.  7).     Before  hurrying  to 


MYDRIATICS.  15 

look  into  a  patient's  eye,  the  beginner  will  feel 
much  more  confident  if  he  has  acquired  previous 
experience,  by  looking  into  one  of  the  many  sche- 
matic eyes  to  be  found  in  the  shops.  While  ad- 
mitting that  the  schematic  eye  has  its  disadvan- 
tages or  imperfections  and  is  not  equal  to  the 
human  eye  in  all  particulars,  yet  it  has  just  those 
qualifications  which  make  it  so  essential  for  the 
beginner  with  the  ophthalmoscope,  namely,  (a)  it 
does  not  wink;  (b)  it  does  not  suffer  from  photo- 
phobia (dread  of  light) ;  (c)  it  does  not  suffer  from 
lacrimation;  (d)  it  does  not  get  tired;  (e)  its  retina 
does  not  suffer  from  light  stimulus;  and,  best  of 
all,  (/)  it  has  a  dilated  pupil. 

Mydriatics.  (Drugs  which  dilate  the  pupil.) 
When  using  the  ophthalmoscope  to  examine  the 
live  eye,  it  is  certainly  an  advantage  to  have  the 
pupil  dilated,  especially  so  for  the  novice,  but  this 
condition  is  often  a  great  inconvenience  to  the  pa- 
tient, and  some  patients  will  positively  refuse  to 
have  any  "  drops  "  used,  while  others  will  permit 
the  use  of  the  drops,  but  find  fault  on  account  of 
the  resulting  discomfort,  and  others  will  have  a 
dread  of  resulting  impaired  sight,  or  another 
patient  might  have  glaucoma  (Chapter  XI.  and 
Plate  XII.),  a  disease  which  would  preclude  the 
use  of  a  drug  which  would  crowd  the  iris  into  the 
angle  of  the  anterior  chamber.  Fortunately  for  the 
beginner  as  well  as  for  the  expert,  with  the  ophthal- 
moscope, the  disc  (optic  nerve  head)  is  the  princi- 


l6  THE   OPHTHALMOSCOPE. 

pal  part  of  the  fundus  usually  affected  by  glaucoma, 
and  it  is  this  part  which  is  most  easily  examined 
without  a  mydriatic.  The  great  thing  therefore 
for  the  student  is  to  learn  to  use  the  ophthalmoscope 
on  the  schematic  eye  and  when  he  has  mastered 
the  technic,  to  then  learn  as  soon  as  possible  to  ex- 
amine the  same  schematic  eye  by  adjusting  to  it 
a  small  pupil  made  by  cutting  a  3^  millimeter 
round  opening  in  a  card.  After  some  considerable 
practice  in  this  way,  sufficient  skill  will  have  been 
obtained  whereby  the  student  will  be  able  to  tell 
when  looking  into  the  human  eye  whether  there 
is  any  disease  present,  and  whether  this  disease 
precludes  the  use  of  a  mydriatic  or  if  it  will 
be  necessary  to  employ  a  mydriatic  so  that  the 
interior  of  the  eye  may  be  studied  more  mi- 
nutely. If  glaucoma  is  not  present  and  there 
are  no  symptoms  of  glaucoma,  then  if  necessary 
for  further  examination,  or  refraction  or  further 
study,  a  mydriatic  may  be  employed.  One  of  the 
safest  mydriatics,  and  one  that  has  but  a  brief  effect 
and  appears  to  have  the  least  amount  of  danger  at- 
tached to  its  use,  as  far  as  the  production  of  glau- 
coma is  concerned,  is  a  fresh  4  per  cent,  solution 
of  cocain ;  one  or  two  drops  of  this  solution  should 
be  placed  on  the  upper  part  of  the  eyeball  as  the 
upper  lid  is  held  upwards  and  the  patient  looks 
downwards;  the  solution  passing  freely  over  the 
cornea  and  its  margins  is  soon  absorbed.  Cocain 
used  in  this  way  will  give  a  maximum  dilation  of 


MYDRIATICS.  17 

the  pupil  in  about  twenty  minutes.  This  dilation 
will  last  for  a  few  hours  ordinarily,  but  as  cocain 
has  very  little,  if  any,  effect  on  the  accommodation, 
the  patient  will  not  object  to  the  temporary  photo- 
phobia, which  passes  away  as  soon  as  the  pupil 
regains  its  normal  size.  After  the  examination  has 
been  completed  under  cocain  mydriasis,  the  writer 
urges  and  advises  counteracting  the  mydriatic  ef- 
fect by  instilling  a  weak  solution  of  eserin,  one 
drop  of  a  l/±  grain  to  the  ounce  of  distilled  water. 
This  is  simply  a  matter  of  extreme  prudence  and 
can  do  no  harm,  but  might  possibly  do  an  immense 
amount  of  good.  A  2  per  cent,  solution  of  euthala- 
min  may  be  used  in  preference  to  cocain.  If  there 
is  any  disease  of  the  interior  of  the  eye  that  is 
injuring  the  sight  or  may  injure  the  sight  later 
on,  then  it  is  certainly  the  part  of  caution  on  the 
part  of  the  surgeon  to  so  inform  the  patient  before 
using  a  mydriatic,  so  that  if  the  patient's  vision 
becomes  impaired  later  on,  the  surgeon  may  not  be 
accused  of  any  wrong  doing  from  having  used 
drops.  In  competent  hands  there  is  very  little  if 
any  danger  from  the  use  of  mydriatics.1  One  drop 

1  Hughlings-Jackson,  Lectures  on  Optic  Neuritis,  Med.  Times  and 
Gazelle,  September  16,  1871 :  "  If  we  use  the  ophthalmoscope,  or  if 
we  use  atropin,  or  if  we  apply  a  blister  to  the  head,  or  adopt  any  new 
kind  of  treatment,  the  patient  may  blame  us  for  his  blindness,  if  he 
saw  well  before  such  procedures.  A  patient  who  reads  the  smallest 
print  and  supposes  his  sight  to  be  good,  may  have  double  optic  neu- 
ritis. The  use  of  atropin  affects  his  sight  for  near  objects  gravely, 
and  if,  from  advance  of  the  neuritic  process,  what  I  may  call  '  retinal 
sight,'  fails  before  the  effect  of  the  atropin  has  passed  off,  he  very 


1 8  THE   OPHTHALMOSCOPE. 

of  a  solution  of  homatropin  hydrobromate  (one 
grain  to  the  ounce  of  water)  will  answer  the  same 
purpose  as  the  cocain  solution,  but  the  effect  is  more 
lasting  and  has  some  action  on  the  accommodation. 
The  Observer.  If  the  observer  has  any  de- 
cided refractive  error,  he  should  wear  his  correct- 
ing glasses,  and  at  the  same  time  should  learn  as 
soon  as  possible  to  relax  his  accommodation  when 
using  the  ophthalmoscope,  so  that  when  he  looks 
at  the  eye  ground  and  has  to  turn  a  lens  in  front 
of  the  sight-hole  to  get  a  clear  picture,  he  will 
know  at  once  that  the  lens  so  used  is  an  approxi- 
mate estimate  of  the  refraction  of  the  eye  being 
examined.  As  a  general  rule,  the  beginner's 
accommodation  makes  him  apparently  myopic  or 
near-sighted,  as  he  strains  his  eye  in  his  efforts  to 
see  the  nerve  or  fundus  about  an  inch  or  two  dis- 
tant, but  he  need  not  worry  or  make  himself  un- 
happy about  this,  but  go  ahead  and  use  any  lens 
that  will  enable  him  to  see  the  nerve  and  eye-ground 
or  whatever  he  wishes-,  and  later  on  he  will  learn 
to  relax  his  accommodation  and  then  use  a  weaker 

naturally  blames  us  for  the  subsequent  permanent  affection  of  his 
sight.  A  patient,  when  asked  how  long  his  sight  had  been  bad,  re- 
plied :  '  Only  since  the  drops  had  been  put  in.'  We  must,  then,  when 
we  discover  neuritis,  sight  being  good,  tell  the  patient  that  his  eyes 
are  not  really  good,  and  that  we  are  anxious  about  his  sight. 
Whether  we  give  this  warning  or  not,  we  shall  be  blamed  by  an  unin- 
telligent patient  for  '  tampering  with  his  eyes.'  We  must,  however, 
act  for  our  patient's  good,  regardless  of  selfish  considerations.  In 
very  many  cases  we  can  see  enough  for  diagnostic  purposes  without 
using  atropin." 


THE    OBSERVER.  19 

lens  at  the  sight-hole.  However,  he  should  not  de- 
lay in  his  efforts  to  learn  to  relax  his  accommoda- 
tion and  the  ability  to  do  so,  he  will  find  one  of  the 
most  difficult  things  in  the  whole  of  ophthalmo- 
scopy,  and  it  will  take  him  some  time  to  accomplish 
it.  There  are  three  reasons  for  the  beginner  to 
wear  any  necessary  correcting  glasses  and  to  learn 
to  relax  his  accommodation,  i.  e.,  (a)  that  he  may 
see  clearly  and  with  the  least  amount  of  effort;  his 
eyes,  in  other  words,  should  be  in  an  emmetropic 
condition  (see  Emmetropia,  p.  71 ) ;  (b)  that  he  may 
not  develop  headaches  and  eye  strain,  and  (c)  that 
he  may  not  count  his  own  refractive  error  as  be- 
longing to,  or  as  a  part  of  the  patient's  eye  con- 
dition, which  he  would  be  very  likely  to  do,  if 
he  did  not  wear  his  glasses  or  make  due  allow- 
ance for  his  own  refractive  error.  A  good  way 
for  the  observer  to  learn  to  relax  his  accommo- 
dation, is  to  place  a  pair  of  plus  three  diopter 
spheres  over  his  correcting  glasses  and  practice 
reading  ordinary  sized  print,  such  as  is  used  in 
this  book,  and  to  read  it  at  thirteen  inches  distant, 
which  is  the  principal  focal  distance  of  the  spheric 
lenses  used.  Another  way  to  relax  the  accommo- 
dation when  looking  into  the  eye,  is  to  imagine 
that  the  eye  ground  or  disc  is  very  distant,  in 
place  of  being  an  inch  or  so  away.  Another  very 
good  way  to  accomplish  the  same  thing,  is  to  learn 
at  once  to  keep  both  eyes  wide  open.  Too  many 
students  will  insist  upon  squinting  one  eye  shut  or 


2O  THE   OPHTHALMOSCOPE. 

holding  it  shut  while  using  the  other  eye,  and  the 
result  is,  they  will  accommodate  several  diopters 
more  than  there  is  any  real  necessity  for  doing. 
This  habit  of  squinting  one  eye  is  a  very  bad  habit 
indeed  and  one  which  many  students  have  had 
great  difficulty  to  overcome.  Another  and  excel- 
lent way  to  learn  to  relax  the  accommodation,  and 
one  which  others  have  appreciated,  is  to  practice 
on  the  schematic  eye.  The  schematic  eye  has  an 
index  which  records  emmetropia,  hypermetropia, 
and  myopia,  so  the  beginner  may  set  the  eye  at  any 
number  of  diopters  of  hypermetropia  or  myopia  and 
then  taking  the  ophthalmoscope  in  hand,  he  must 
learn  to  see  the  eye  ground  of  the  schematic  eye 
with  the  lens  at  the  sight-hole  in  the  ophthalmoscope 
which  corresponds  to  the  amount  of  the  refractive 
error  indicated  by  the  index.  For  instance,  if  the 
schematic  eye  is  set  for  3  D.  of  hypermetropia,  then 
the  +  3  D.  must  be  turned  into  the  sight-hole  of 
the  ophthalmoscope,  when  the  observer  views  the 
eye  ground,  and  he  must  learn  to  see  the  details 
of  the  fundus  with  this  +  3  D.  and  no  other  lens. 
The  approximate  estimation  of  the  various  refrac- 
tive errors,  will  become  comparatively  easy  as  soon 
as  the  student  learns  to  relax  his  accommodation. 
This  will  be  referred  to  later  (Chapter  II.). 

Position  of  the  Observer.  The  observer  should 
be  comfortably  seated  at  the  side  of  the  patient  cor- 
responding to  the  eye  he  is  to  examine,  if  examin- 
ing the  right  eye,  the  observer  should  be  on  the 


POSITION    OF    LIGHT.  21 

patient's  right;  if  the  left  eye,  then  on  the  pa- 
tient's left  side.  When  examining  the  right  eye 
the  ophthalmoscope  is  held  in  the  right  hand 
and  before  the  right  eye  (Fig.  8) ;  and  in  the  left 
hand  and  before  the  left  eye  when  examining  the 
left  eye.  The  examiner's  eye  should  be  a  little 
above  or  higher  than  the  patient's  eye.  The  ex- 
aminer's head  should  be  tilted  slightly  in  the  di- 
rection of  his  shoulder  corresponding  to  the  eye 
he  is  using  (Fig.  9). 

To  meet  all  the  requirements  for  the  comfort  of 
the  observer,  he  will  do  well  to  have  a  stool  with 
revolving  top  or  seat,  that  he  may  adjust  his  posi- 
tion promptly  and  to  suit  the  individual  patient. 

Position  of  Light.  If  the  mirror  on  the  oph- 
thalmoscope is  of  40  centimeter  radius,  then  to 
begin  the  examination,  the  light  should  be  about 
this  distance  to  one  side  and  back  of  the  patient 
and  on  a  level  with  the  patient's  eye ;  in  other  words, 
the  light  should  be  placed  at  an  angle  of  45  degrees 
with  the  plane  of  the  patient's  face,  so  as  to  illumi- 
nate the  outer  half  of  the  eye-lashes  of  the  eye  to  be 
examined,  and  it  may  be  well  also  to  have  the  tip 
of  the  patient's  nose  illuminated  at  the  same  time 
(Fig.  8).  The  beginner  should  appreciate  these 
points  of  position,  for  if  the  light  cannot  take 
this  direction  from  the  flame,  and  the  flame  should 
be  back  of  the  patient's  ear,  then  there  cannot  be 
any  reflection  from  the  mirror  when  close  in  front 
of  the  patient's  eye,  as  the  temple  and  ear  would 


22  THE   OPHTHALMOSCOPE. 

cut  off  the  light  from  the  mirror.  Many  students 
when  learning  to  use  the  ophthalmoscope,  neglect 
this  position  of  the  light,  and  when  they  get  close 
to  the  eye  to  examine  it,  lose  the  reflection  and 
wonder  why  they  lose  it. 

Position  of  Patient.  The  patient  should  be 
seated  in  a  comfortable  chair  without  arms  (Fig. 
8),  and  be  instructed  to  look  straight  ahead  into 
vacancy,  or  across  the  room  at  some  large  object 
about  on  a  level  with  his  eyes;  in  this  way  his  ac- 
commodation will  relax  considerably  and  his  pupil 
will  be  larger.  He  is  also  instructed  to  change  the 
direction  of  his  vision  only  when  told  to  do  so. 
Under  no  circumstances  should  the  patient  be  al- 
lowed to  look  at  a  light  or  into  the  mirror,  as  the 
light  stimulus  falling  upon  the  macula,  will  cause 
the  pupil  to  contract.  If  the  patient  is  a  child  and 
will  not  concentrate  the  vision  as  just  directed, 
then  it  will  be  necessary  to  have  some  one  stand 
back  of  the  observer,  and,  by  snapping  the  fingers 
or  clapping  the  hands,  or  dangling  a  bunch  of  keys 
or  a  watch,  attract  the  child's  attention,  and  thus 
keep  it  from  looking  into  the  mirror.  If  the  pa- 
tient has  a  squint,  it  will  be  necessary  when  ex- 
amining the  squinting  eye  to  have  the  fixing  eye 
covered  with  a  folded  handkerchief,  or  held  gently 
shut  with  the  finger,  or  shielded  with  a  card,  and 
in  this  way  the  squinting  eye  will  ordinarily  turn 
straight  and  the  observer  will  have  an  opportunity 
to  examine  it.  With  children  it  may  be  necessary 


POSITION    OF    PATIENT. 


24  THE   OPHTHALMOSCOPE. 

to  employ  the  indirect  method  (Fig.  13).  The 
patient  and  observer  should  each  keep  both  eyes 
open.  The  one  exception  to  this,  is  when  the  pa- 
tient has  a  squint  as  just  stated. 

How  to  Hold  the  Ophthalmoscope.  The  ob- 
server should  hold  the  ophthalmoscope  as  vertical 
as  possible  and  have  the  sight-hole  directly  in  front 


FIG.  9. — Correct  position  of  holding  the  ophthalmoscope.  Top  of  in- 
strument resting  in  the  hollow  of  the  brow  and  the  side  resting  on  or 
touching  the  side  of  the  nose.  Ophthalmoscope  is  held  vertically  before 
the  right  eye  and  the  observer's  head  is  inclined  slightly  toward  the 
right  shoulder  with  the  arm  close  to  the  side.  Without  changing  the 
position  of  the  instrument  the  observer  can  easily  turn  the  milled  wheel 
with  the  tip  of  his  index  finger,  as  shown  in  Fig.  10. 


HOW   TO    HOLD   THE   OPHTHALMOSCOPE.          25 

of  his  pupil  and  close  to  his  eye.  The  upper  mar- 
gin of  the  ophthalmoscope  resting  in  the  hollow 
of  the  brow,  and  the  side  of  the  instrument  against 
the  side  of  the  nose  (Fig.  9).  The  observer's  arm 
should  be  at  his  side  and  not  form  an  angle  with 


FIG.  10. — Very  faulty  position  of  holding  the  ophthalmoscope  for  direct 
examination.  The  arm  and  hand  and  handle  of  the  ophthalmoscope  are 
turned  outward.  The  index  finger,  however,  is  in  the  correct  position 
for  turning  the  milled  wheel,  as  referred  to  in  Fig.  9. 

his  body.  If  the  arm  of  the  hand  holding  the 
ophthalmoscope  is  bent  outward  (Fig.  10),  and 
not  kept  vertical,  then  when  the  observer  gets 
close  to  the  patient's  eye  his  hand  is  liable  to,  and 

4 


26  THE   OPHTHALMOSCOPE. 

very  likely  will,  strike  the  patient's  nose,  an  evi- 
dent indication  of  want  of  skill  or  experience. 

How  to  Use  the  Ophthalmoscope.  There  are 
two  ways,  or  methods,  of  using  the  ophthalmo- 
scope; one  is  called  the  direct,  and  the  other  the 
indirect  method.  The  direct  method  (Fig.  8) 
gives  an  erect,  virtual,  and  enlarged  image  of  the 
interior  of  the  eye,  while  the  indirect  method  (Fig. 
13)  gives  or  produces  an  inverted  and  real  image, 
but  much  less  magnified  than  the  direct.  The 
principle  of  the  direct  method  is  similar  to  a  sim- 
ple microscope,  and  the  indirect  to  a  compound 
microscope. 

The  Direct  Method.  Executing  the  several 
details  as  just  given  as  regards  the  room,  the 
light,  etc.,  the  observer  begins  his  examination 
at  a  distance  of  25  or  30  centimeters  from  the 
eye,  never  closer,  and  at  this  distance  he  re- 
flects the  light  into  the  eye  and  observes  a  "  red 
glare  "  which  occupies  the  previously  black  pupil. 
This  red  glare  is  called  the  "  reflex  "  and  is  due 
to  the  reflection  from  the  choroidal  (vascular) 
coat  of  the  eye.  The  color  of  this  reflex  varies, 
(a)  with  the  size  of  the  pupil,  (b)  transparency 
of  the  media  (cornea,  aqueous,  lens  and  vitreous), 
(c)  the  refraction,  (d)  the  amount  of  pigment  in 
the  eye  ground,  and  (e)  with  detachment  of  the 
retina,  growths,  etc.  Having  obtained  the  reflex, 
it  will  be  well  for  the  observer  to  practice  keeping 
the  light  on  the  pupil,  by  changing  his  distance 


SIZE    OF    IMAGE.  2J 

while  still  holding  the  ophthalmoscope  in  front  of 
his  eye,  approaching  the  eye  as  close  as  an  inch 
or  two;  this  must  be  done  slowly  and  not  with  a 
rush.  The  direct  method,  therefore,  is  so  called 
from  the  fact  that  the  observer  looks  directly  into 
the  eye.  A  detailed  description  of  the  eye  ground 
is  given  in  Chapter  IV. 

Size  of  the  Image  of  the  Eye  Ground.  In  this 
direct  method  of  looking  into  the  eye,  the  optic 
nerve  head,  retinal  vessels,  etc.,  are  all  enlarged 
on  account  of  the  strong  refracting  or  magnify- 
ing power  of  the  cornea  and  lens;  the  result  is, 
that  on  account  of  the  enlargement  the  eye  ground 
seems  to  be  at  some  distance  behind  the  eye  (Figs, 
ii  and  12).  The  nerve  head  in  an  emmetropic 
eye,  as  seen  with  the  ophthalmoscope,  appears 
about  25  millimeters  in  diameter,  and  about  250 
millimeters  distant.  The  actual  distance  of  this 
nerve  head  from  the  nodal  point  in  the  lens,  is 
about  15  millimeters,  therefore  the  actual  size  of 
the  nerve  head  must  be  15/250  of  25,  or  3/2,  or 
1.5  millimeters;  then  15,  the  nodal  distance,  is  to 
the  supposed  distance,  250  millimeters,  as  the  ac- 
tual size,  1.5  is  to  the  magnified  size,  25;  which  is 
16.6,  the  magnification;  or,  to  put  it  mathematically 

15:250::  1.5:25=16.6. 

In  other  words,  when  the  emmetropic  nerve  head 
is  observed,  it  appears  about  16.6  times  larger  than 
it  actually  is.  The  disc  of  a  hypermetropic  eye 


28 


THE    OPHTHALMOSCOPE. 


appears  smaller  than  that  of  an  emmetropic  eye, 
and  the  disc  of  a  myopic  eye  appears  larger.  Just 
as  the  nerve  head  appears  magnified,  so  the  ves- 
sels of  the  eye  ground  appear  correspondingly 


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THE    INDIRECT    METHOD. 


of  an  inch.    The  capillaries  of  the  retina  in  health 
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in  addition  to  his  ophthalmoscope.  The  convex 


THE   OPHTHALMOSCOPE. 


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THE    INDIRECT    METHOD.  31 

lens  which  comes  in  the  case  with  the  ophthalmo- 
scope (+  16  D.)  is  usually  too  strong  and  of  too 
small  aperture,  and  on  this  account  the  writer 
prefers  his  condensing  lens,  as  pictured  in  Fig. 


FIG.    14. — Author's    Condensing    Lens.     Two-thirds  size. 

14  (reduced  one-third  in  size).  This  lens  has  a 
metal  rim  which  assists  in  preserving  the  lens 
from  breakage  and  a  convenient  handle  which 
makes  it  much  easier  to  manipulate.  To  make 
the  indirect  examination,  the  light  (as  bright  as 
possible)  may  be  placed,  (i)  as  in  the  direct 
method,  and  the  observer  may  keep  his  position 
at  the  side  of  the  patient  corresponding  to  the 
eye  to  be  examined,  or  (2)  the  light  may  be  placed 
above  the  patient's  head,  or  (3)  on  a  level  with 
the  top  of  the  patient's  head.  It  is  customary 
with  many  observers  to  take  a  seat  in  front  of 
the  patient,  but  this  is  not  at  all  necessary,  and  in 
fact  it  is  sometimes  quite  unnecessary  and  rather 
to  be  avoided.  Whether  the  observer  sits  at  one 
side  or  in  front  of  the  patient,  his  eye  should  be 


32  THE   OPHTHALMOSCOPE. 

about  16  or  20  inches  from  the  eye  under  obser- 
vation, when  beginning  the  examination.  At  this 
distance  and  the  light  in  position,  with  the  patient's 
right  eye  to  be  examined,  the  observer  holds  the  con- 
densing lens  with  his  thumb  and  index  finger  of 
his  left  hand,  and  rests  his  little  and  ring  fingers 
on  the  patient's  right  temple  or  forehead,  so  that 
the  condensing  lens  is  about  two  or  three  inches 
from  the  eye.  Then,  with  the  ophthalmoscope 
held  in  the  usual  position  before  his  right  eye,  the 
observer  reflects  the  light  through  the  condens- 
ing lens  into  the  eye  and  very  slowly  approaches 
or  moves  back  from  the  eye  until  he  recognizes 
a  retinal  vessel  or  the  optic  disc;  he  must  remem- 
ber, however,  that  he  is  not  looking  into  the  eye, 
but  is  viewing  an  aerial  image  of  the  eye  ground 
formed  in  the  air  between  the  condensing  lens  and 
the  ophthalmoscope.  This  image,  besides  being 
aerial,  is  inverted,  and  has  undergone  lateral  in- 
version, so  that  the  right  side  of  the  eye  ground 
becomes  the  left  side  of  the  image,  and  the  left 
side  of  the  eye  ground  becomes  the  right  side  of 
the  image,  the  upper  portion  of  the  eye  ground 
becomes  the  lower  portion  of  the  image,  the  lower 
portion  of  the  eye  ground  becomes  the  upper  por- 
tion of  the  image  (Fig.  15).  While  making  this 
examination  the  patient  is  directed  to  look  straight 
ahead,  then  to  gradually  turn  the  eye  in  various 
directions  to  suit  the  observer's  wishes.  In  this 
way,  various  portions  of  the  eye  ground  are  care- 


THE    INDIRECT    METHOD. 


33 


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the  principal  part  of  the  eye  ground  or  part  of 
the  image  first  looked  for,  and  to  bring  it  into 


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view  at  once  the  patient  is  told  to  look  a  little  to 
the  observer's  right  when  examining  the  right 
eye,  and  to  the  observer's  left  when  examining 
the  left  eye.  It  has  already  been  mentioned  that 


34  THE    OPHTHALMOSCOPE. 

the  patient  should  be  told  to  rotate  his  eye  in  dif- 
ferent directions  as  the  observer  tells  him,  but 
this  is  not  always  satisfactory,  as  many  patients 
will  turn  the  eye  too  far,  and  therefore  it  may  be 
just  as  well  to  have  a  nervous  patient  fix  his  gaze  in 
one  direction  and  let  the  observer  learn  to  move  the 
lens,  slowly  upward,  downward,  inward,  outward 
and  diagonally.  The  observer  must  also  learn  to 
move  the  lens  closer  to  the  eye  or  to  bring  it  away 
from  the  eye,  as  necessary,  and  in  this  way  get  the 
most  distinct  image.  It  may  be  necessary  at  times  to 
rotate  the  lens  on  its  axis.  The  stronger  the  con- 
densing lens  employed,  the  larger  the  view  of  the 
fundus,  but  the  details  will  be  smaller;  the  weaker 
the  condensing  lens,  the  smaller  will  be  the  view 
of  the  fundus,  but  with  larger,  magnified  individ- 
ual points  in  the  image-  To  relieve  the  observer's 
accommodation  and  to  magnify  the  aerial  image 
la  plus  four  lens  is  usually  placed  at  the  sight-hole 
of  the  ophthalmoscope.  This  plus  four  lens,  cor- 
responds to  the  eye  piece  of  the  microscope;  when 
examining  eyes  that  are  highly  myopic  it  may  be 
omitted.  Practicing  the  indirect  method,  the  ob- 
server sees  a  larger  part  of  the  eye  ground  at  one 
time  than  by  the  direct  method,  but  it  is  not  mag- 
nified to  the  same  extent  as  in  the  direct  method. 
It  is  a  method,  however,  that  is  easier  and  more 
convenient  in  many  ways  than  the  direct,  and  yet 
many  ophthalmologists  neglect  to  use  it.  It  is  a 
method  too  that  does  not  necessarily  require  a 


THE    INDIRECT    METHOD.  35 

dilated  pupil.  It  is  a  method  that  is  occasionally 
of  great  convenience  in  the  clinic,  when  objection- 
able (unclean)  patients  come  for  examination,  and 
the  physician  desires  to  keep  at  a  good  distance. 
Both  the  direct  and  indirect  methods  should  be 
practiced  and  they  are  comparatively  easy  when 
the  patient  has  large  pupils,  but  with  very  small 
pupils  a  detailed  and  satisfactory  examination, 
while  it  may  be  obtained,  is  often  difficult.  When 
practicing  the  indirect  method,  the  observer  should 
keep  both  eyes  open  as  with  the  direct  method. 
And  he  may  use  his  right  eye  when  looking  at  the 
patient's  right  eye,  and  his  left  when  looking  at 
the  patient's  left,  or  he  may  use  his  right  eye  in 
each  instance.  This  is  purely  a  matter  of  conveni- 
ence. While  viewing  the  disc  with  the  indirect 
method,  some  approximation  of  the  refraction  may 
be  obtained  when  the  condensing  lens  is  gradu- 
ally withdrawn  from  the  eye. 

1.  When  the  image  of  the  disc  appears  to  in- 
crease in  size,  the  refraction  is  myopic;  and  if 

2.  The  image  of  the  disc  diminishes  in  size,  the 
refraction  is  hypermetropic ;  and  if 

3.  The  image  of  the  disc  does  not  change  in 
size,  it  is  emmetropic. 

4.  For  astigmatism.     If  the  image  of  the  disc, 
which  is  the  part  usually  selected  for  making  this 
estimate,  appears  of  uniform  size  in  one  meridian, 
whether  the  condensing  lens  is  brought  closer  to 
or  removed  from  the  eye,  then  that  meridian  is 


36  THE   OPHTHALMOSCOPE. 

emmetropic,  but  if  the  meridian  grows  smaller  as 
the  lens  is  withdrawn  from  the  eye,  then  that  me- 
ridian is  hypermetropic,  if  it  grew  larger  then  it 
would  be  myopic.  Withdrawing  the  condensing 
lens  and  all  meridians  appear  to  grow  smaller  but 
one  more  so  than  the  other  then  the  condition  is 
one  of  compound  hypermetropia.  If  all  meridians 
grew  larger  but  one  more  so  than  another  then 
the  condition  would  be  one  of  compound  myopic 
astigmatism. 

The  image  growing  smaller  in  one  meridian  and 
larger  in  the  other,  as  the  condensing  lens  is  with- 
drawn from  the  eye,  would  signify  mixed  astig- 
matism. 

To  study  the  presence  of  an  elevation  of  the 
disc  or  the  elevation  of  a  growth  or  detachment, 
or  to  study  the  depth  of  a  cupping  of  the  disc,  then 
after  getting  the  aerial  image  and  moving  the  ob- 
jective lens  from  side  to  side  and  up  and  down, 
the  near  points  of  the  image  will  appear  to  move 
faster  than  the  points  beyond;  this  is  known  as 
the  parallactic  movement. 

The  Size  of  the  Image  of  the  Eye  Ground. 
This  depends  upon  the  refraction  of  the  eye  and 
the  distance  of  the  convex  lens  from  the  eye  under 
examination.  In  the  standard  (emmetropic)  eye 
the  size  of  the  image  is  always  the  same,  no  mat- 
ter how  far  away  from  the  eye  the  convex  lens  is 
held.  To  estimate  the  size  of  the  image,  as  seen 
in  the  standard  eye,  all  that  is  necessary  to  know 


OBLIQUE    ILLUMINATION.  37 

is  the  principal  focus  of  the  condensing  lens  em- 
ployed: if  +  13  D.,  then  the  image  is  formed  at 
about  75  millimeters  (three  inches),  and  remem- 
bering that  the  nerve  head  in  the  standard  eye  is 
15  millimeters  back  from  the  nodal  point,  the  size 
of  the  image  will  be  to  the  size  of  the  nerve  head, 
(if  that  is  what  is  looked  at  in  the  image)  as  their 
respective  distances  from  the  nodal  point  and  con- 
densing lens,  or  as  15  is  to  75,  which  equalsj^  the 
magnification.  Comparing  the  two  methods  of  ex- 
amination, the  direct  and  the  indirect,  the  former, 
while  it  gives  a  smaller  view  of  the  fundus,  yet  it 
is  greatly  magnified,  sixteen  times  as  compared  to 
five  by  the  indirect,  hence  for  the  examination  of 
a  minute  point,  such  as  a  hemorrhage  or  growth 
or  foreign  substance,  small  detachment,  etc.,  the 
direct  method,  is  far  superior  to  the  indirect.  The 
direct  method  gives  an  erect  image  and  the  ob- 
server recognizes  at  once  each  point  of  the  eye 
ground  in  its  correct  anatomic  position.  With  the 
direct  method  the  observer  can  turn  a  lens  into 
the  sight-hole  of  the  ophthalmoscope,  which  ap- 
proximately corrects  the  refractive  error  of  the 
eye  under  observation. 

Oblique  Illumination,  or  Focal  Illumination. 
The  cornea,  aqueous  humor,  lens  and  anterior  por- 
tion of  the  vitreous  body,  should  have  careful  con- 
sideration, for  a  clear  view  of  the  eye  ground 
depends  upon  the  transparency  of  these  media. 
This  is  a  most  important  part  of  the  examination 


THE   OPHTHALMOSCOPE. 


O15LIOUK    ILLUMINATION. 


39 


H         <L>         «H 

•*-•    <n 


£•  '" 
'S   •-• 


4O  THE   OPHTHALMOSCOPE. 

and  the  cautious  physician  will  not  omit  this  part 
of  the  study,  especially  if  a  clear  view  of  the  eye 
ground,  cannot  be  obtained  with  the  ophthalmo- 
scope. This  method  of  examination  is  called  the 
oblique  or  focal,  because  the  light  is  usually  con- 
densed from  the  side  by  means  of  a  lens  and  made 
to  fall  successively  upon  and  into  the  cornea,  aque- 
ous humor,  lens  and  anterior  portion  of  the  vitre- 
ous humor.  The  source  of  light  or  illumination, 
lamp  or  gas  flame,  is  placed  one  or  two  feet  from 
the  head  of  the  patient  and  to  the  side  correspond- 
ing to  the  eye  to  be  examined,  and  at  the  same 
time  a  little  to  the  front  and  above  the  level  of 

the  eye  (Fig.  16).  A  con- 
vex lens  of  short  focus, 
+  13  D.  or  +  16  D.,  is  held 
in  the  hand  of  the  surgeon, 
between  the  light  and  the 
eye  under  examination,  and 
about  three  inches  from  the 
eye,  so  that  the  converging 

FIG.  1 8.— Loupe.  J 

pencil     from     the     lens     is 

thrown  upon  and  into  the  eye.  As  the  lens  is 
moved  from  side  to  side  and  up  and  down  and 
diagonally,  each  part  of  the  cornea,  aqueous  and 
iris  may  be  carefully  inspected.  Or,  in  place  of 
moving  the  condensing  lens,  it  may  be  held  still, 
and  the  patient  told  to  rotate  the  eye  in  certain 
given  directions.  When  a  minute  point,  is  to 
be  carefully  examined  by  itself,  then  the  con- 


OBLIQUE    ILLUMINATION. 


U      to 

J5     C    £ 

H  £    c 


2  i  1 

o  rt  ~ 


e.  ^ 


42  THE   OPHTHALMOSCOPE. 

densing  lens,  must  be  moved  closer  to  the  eye  or 
away  from  it  until  the  apex  of  the  cone  of  con- 
verging rays  will  fall  directly  upon  the  point  se- 
lected. To  study  the  anterior  layers  of  the  vitre- 
ous and  the  peripheral  portions  of  the  lens  of  the 
eye,  it  is  often  necessary  to  dilate  the  pupil,  and 
the  light  must  now  be  placed  a  little  more  to  the 


FIG.  20. — Cover  chimney  with  condensing  lens. 

front  of  the  eye  under  examination  (Fig.  19). 
The  patient's  head  should  also  be  tilted  a  little 
backwards  and  the  observer  must  get  a  little  to 
one  side,  so  as  not  to  intercept  the  rays  from  the 
light.  If  the  observer  wishes  to  magnify  the  part 
under  examination,  he  may  do  so  by  holding  an- 
other lens  of  the  same  focus,  or  of  stronger  power, 
between  the  thumb  and  index  finger  of  his  other 
hand,  and  gaze  at  the  spot  through  this  second 
lens  (Fig.  17).  Another  convenient  way  to  mag- 
nify the  part  looked  at,  or  to  examine  for  foreign 
substances  (cinders,  etc.)  is  to  use  a  "  loupe."  This 


OBLIQUE    ILLUMINATION.  43 

is  pictured  in  Figs.  18  and  19.  A  very  good  way  to 
condense  the  light  onto  the  cornea  when  the  sur- 
geon wishes  to  use  his  hands  for  another  purpose, 
for  instance  when  removing  a  foreign  substance, 
is  to  have  a  strong  lens  from  the  trial  case  placed 
in  the  notch  in  front  of  the  iris  diaphragm,  on  the 
cover  chimney,  or  to  use  a  cover  chimney  with  tele- 
scopic attachment  as  shown  in  Fig.  20. 


CHAPTER   II. 

OPTICS.  LIGHT.  REFLECTION.  REFRACTION.  LENSES. 
HYPERMETROPIA.  MYOPIA.  ASTIGMATISM.  ESTIMAT- 
ING THE  REFRACTION  BY  THE  DIRECT  AND  INDIRECT 
METHODS  AND  RETINOSCOPY. 

To  assist  the  beginner  in  ophthalmoscopy,  who 
should  have  a  general  knowledge  of  the  optic  prin- 
ciples on  which  the  ophthalmoscope  is  constructed, 
and  also  the  optic  principles  of  the  eye  he  is  to  ex- 
amine, the  writer  has  prepared  this  chapter,  bor- 
rowing freely  from  his  work  on  "  Refraction  and 
How  to  Refract." 

Light.  Light  is  that  form  of  energy  which 
acting  upon  the  organ  of  sight  renders  visible  the 
object  from  which  it  proceeds.  This  energy  is  prop- 
agated in  waves  in  all  directions  from  a  luminous 
body  and  with  a  velocity  in  a  vacuum  of  186,000 
miles  in  a  second  of  time.  In  the  study  of  a  lumi- 
nous substance  such  as  a  candle,  lamp  or  gas  flame, 
the  substance  itself  must  not  be  considered  as  a  sin- 
gle source  of  radiation,  but  as  a  collection  of  innu- 
merable points  of  light,  from  every  one  of  which 
waves  or  rays  proceed  in  all  directions  and  cross  one 
another  as  they  diverge  from  their  respective  points. 
In  other  words,  all  rays  of  light  proceeding  from  a 
point  are  divergent. 

Intensity  of  Light.     The  intensity  of  light  di- 

44 


RAYS.  45 

minishes  as  the  square  of  the  distance ;  for  example, 
if  an  object  is  twice  as  far  from  a  luminous  body 
as  another  of  the  same  size,  it  will  receive  one- 
fourth  as  much  light  as  the  latter.  Fig.  21  shows 


FIG.  21. 

rays  of  light  illuminating  a  card  about  one  inch  and 
a  half  away  from  the  candle  flame,  and  the  second 
card  just  the  same  size,  at  twice  this  distance  re- 
ceives only  one-fourth  the  amount  of  illumination. 
If  the  second  card  had  been  four  times  as  far  away 
it  would  have  received  only  one-sixteenth  as  much 
illumination. 

Ray.  Ray  from  radius,  meaning  a  straight 
line,  is  a  word  used  in  optics  in  preference  to 
wave,  and  means  the  smallest  subdivision  of  light. 
Rays  of  light  are  considered  as  incident,  emergent, 
reflected,  refracted,  divergent,  parallel  and  con- 
vergent. 

Incident  Rays.  Rays  of  light  are  said  to  be 
incident  when  they  strike  or  fall  upon  the  surface 
of  an  object.  Rays  of  light  from  the  candle  in 
Fig.  21  falling  upon  the  card  are  incident  rays. 
These  rays  are  also  spoken  of  as  divergent  rays. 

Emergent  Rays.     Rays  of  light  are  emergent 


46 


THE    OPHTHALMOSCOPE. 


when  they  have  traversed  or  passed  through  a 
transparent  substance.  This  is  demonstrated  or 
shown  by  the  incident  or  parallel  rays  in  Fig.  22, 


FIG.  22. 

which  have  undergone  refraction  by  the  plano- 
convex lens,  and  are  now  emergent;  these  latter 
rays  in  this  instance  are  also  spoken  of  as  con- 
vergent. 

Reflected  Rays.  Rays  of  light  are  reflected 
when  they  rebound  from  a  polished  surface. 
This  is  shown  in  Fig.  23.  See  Laws  of  Reflection. 


FIG.  23. 


Refracted  Rays.    Rays  are  refracted  when  they 
are  deviated  from  their  course  in  passing  through 


RAYS.  47 

any  transparent  substance.  This  is  shown  in 
Fig.  22;  as  the  rays  emerge  from  the  lens  they 
are  deviated  from  their  course. 

Divergent  Rays.  Rays  of  light  proceed  diver- 
gently from  any  luminous  substance,  but  in  the 
study  of  refraction  only  those  rays  which  proceed 
from  a  point  closer  than  six  meters  (20  feet)  are 
spoken  of  as  divergent.  This  is  also  shown  in 
Fig.  21  as  the  rays  diverge  from  the  candle  flame 
and  are  also  spoken  of  in  this  instance  as  incident. 

Parallel  Rays.  The  greater  the  distance  of  any 
luminous  point,  the  more  nearly  do  its  rays  ap- 
proach to  parallelism;  this  is  evident  in  a  study  of 
rays  coming  from  such  distant  sources  as  the  sun, 
moon  and  stars.  For  all  practical  purposes  in  the 
study  of  refraction,  rays  of  light  which  proceed 
from  a  distance  of  six  meters  or  more  are  spoken 
of  as  parallel,  although  this  is  not  absolutely  cor- 
rect, as  rays  of  light  at  this  distance  still  maintain 
a  slight  amount  of  divergence.  If  the  pupil  of  the 
emmetropic  eye  is  represented  by  a  circular  open- 
ing four  millimeters  in  diameter,  then  the  rays  of 
light  from  a  luminous  point  at  six  meters  (6,000 
millimeters)  will  have  a  divergence  of  4/6,000 
when  they  enter  such  a  pupil. 

Convergent  Rays.  Convergent  rays  are  the  re- 
sult of  refraction  through  a  convex  lens  or  reflec- 
tion from  a  concave  mirror.  Convergent  rays  are 
not  a  condition  of  nature.  Fig.  22  shows  the  rays 
of  light  converging  as  they  emerge  from  the  lens, 


48  THE   OPHTHALMOSCOPE. 

and  Fig.  23  shows  the  rays  of  light  converging  as 
they  rebound  from  the  concave  mirror. 

A  Beam  of  Light.  This  is  a  series  or  collection 
of  parallel  rays.  Fig.  22,  if  reversed,  shows  rays 
of  light  diverging  from  a  point  and  after  refrac- 
tion by  the  plano-convex  lens  are  made  parallel. 
A  Pencil.  A  pencil  of  light  is  a  collection  of 
divergent  or  convergent  rays.  Convergent  rays 
are  those  which  tend  to  a  common  point,  whereas 

divergent  rays  are 
those  which  proceed 
from  a  point.  This 
point  is  called  a  ra- 
diant point.  The 
rays  from  the  candle 

FIG.  24. 

flame  in  Fig.  24  form 

a  divergent  pencil,  the  point  in  the  flame  is  the 
point  of  the  pencil  or  the  radiant  point.  The  rays 
of  light  coming  together  after  leaving  the  lens,  as 
shown  in  Fig.  22,  form  a  convergent  pencil.  The 
point  of  this  converging  pencil  is  called  a  |oettsr— 

A  Focus.  This  is  the  point  of  a  converging  or 
diverging  pencil.  The  center  of  a  circle  is  also 
spoken  of  as  a  focus.  Focus  means  "  fire,"  and 
is  referred  to  as  the  burning  point  of  a  convex  lens. 
There  are  two  kinds  of  foci. 

A  Positive  or  Real  Focus.  This  is  the  point  to. 
which  rays  of  light  are  directed  after  passing 
through  a  convex  lens  ( Fig.  22 ) ,  or-  the  point  to 


REFLECTION.  49 

which  rays  of  light  are  directed  after  reflection 
from  a  concave  mirror  (Fig.  23).  A  positive  or 
real  focus  may  be  described  as  the  actual  meeting 


ofrays  of  light;  such  a  focus  may  be  thrown  upon 
a  screen. 

A  Negative  or  Virtual  Focus.  This  is  the 
point  from  which  rays  appear  to  diverge  after  pass- 
ing through  a  concave  lens  (Fig.  45)  or  after  re- 
flection from  a  convex  mirror  (Fig.  31)  or  after 
refraction  through  a  convex  lens  when  the  light 
or  object  is  closer  to  the  lens  than  its  principal  focus 
(Fig.  47),  or  after  reflection  from  a  concave  mir- 
ror when  the  light  or  object  is  closer  to  the  mirror 
than  its  principal  focus  (Fig.  28).  A  virtual  or 
negative  focus  cannot  be  thrown  upon  a  screen. 

Reflection.  From  the  Latin  "  reflectere,"  to  re- 
bound. This  is  the  sending  back  of  the  rays  of 
light  by  the  surface  on  which  they  fall  into  the 
medium  through  which  they  came.  This  is  the 
study  of  catoptrics  (from  the  Greek  x(*T07rTPov 
meaning  "a  mirror").  While  most  of  the  rays 
of  light  falling  upon  a  transparent  substance  will 
pass  through  it,  yet  some  portion  of  the  rays  are 
reflected  and  it  is  by  virtue  of  these  reflected  rays 
that  surfaces  are  rendered  visible.  A  substance 
that  could  transmit  or  absorb  all  the  rays  of  light 
which  came  to  it  (if  such  a  substance  existed) 
would  be  invisible.  Fig.  33  shows  a  ray  of  light 
incident  on  a  piece  of  clear  glass ;  a  portion  of  this 
ray  passes  through,  emerges  and  is  refracted,  but 
6 


5O  THE   OPHTHALMOSCOPE. 

at  the  same  time  all  of  the  incident  ray  did  not 
pass  through  the  glass,  a  portion  of  it  rebounded 
or  was  reflected,  and  in  this  way  the  glass  is  made 
or  rendered  visible.  Likewise  the  ray  P,  while 
it  strikes  the  glass  perpendicularly,  a  portion  of 
it  passes  through  the  glass  and  a  portion  rebounds 
in  the  same  perpendicular,  and  if  the  eye  was  look- 
ing down  onto  or  into  or  through  the  glass,  the 
glass  itself  would  be  rendered  visible. 

Laws  of  Reflection.  ( i )  The  angle  of  reflection 
is  equal  to  the  angle  of  incidence.  (2)  The  re- 
flected and  incident  rays  are  in  the  same  plane 
with  the  perpendicular  to  the  surface  (Fig.  25). 
The  incident  ray  /  falling  upon  the  plane  mir- 
ror AB  at  D  becomes 
the  reflected  ray  R. 
The  perpendicular  line 
P  divides  the  angle 
IDR  into  two  angles  of 

n  D 

the     same     size,     IDP 
and  RDP.     The   angle 

of  reflection  RDP  is  equal  to  the  angle  of  incidence 
IDP.  If  the  angle  of  incidence  was  made  greater 
then  the  angle  of  reflection  would  be  greater,  if 
the  angle  of  inpidence  was  made  smaller  then  the 
angle  of  reflection  would  also  be  made  smaller. 
The  reflected  ray  R  and  the  incident  ray  /  are  in 
the  same  plane  as  the  perpendicular  P.  The  bril- 
liancy of  reflection  is  controlled  by  the  quality  of 
the  reflecting  surface  upon  which  .the  light  is  inci- 


REFLECTION  FROM  A  PLANE  MIRROR.     51 

dent.  Polished  surfaces  or  surfaces  light  in  color 
reflect  with  great  intensity,  whereas  rough  sur- 
faces or  surfaces  dark  in  color  reflect  very  im- 
perfectly. 

Reflection  from  a  Plane  Mirror.  Rays  of  light 
are  reflected  from  a  plane  mirror  in  the  same  di- 
rection in  which  they  fall  upon  it;  if  parallel,  con- 
vergent, or  divergent  before  reflection,  then  they 
are  parallel,  convergent  or  divergent  after  reflec- 
tion. An  object  in  front  of  a  plane  mirror  appears 


FIG.  26. 


just  as  far  back  in  the  mirror  as  the  object  is  in 
front  of  it  (Fig.  26).  AB  represents  a  plane  mirror 
with  EF  rays  from  the  extremes  of  the  object  / 
reflected  from  the  mirror  AB  and  meeting  at  the 
observer's  eye  as  if  they  came  from  the  object  / 
in  the  mirror.  The  apparent  distance  of  the  object 
7  (as  pictured  in  the  mirror)  from  the  observer's 
eye,  is  equal  to  the  combined  length  of  the  incident 
and  the  reflected  rays.  The  appearance  of  an 


52  THE   OPHTHALMOSCOPE. 

image  in  a  plane  mirror  is  not  exactly  the  same  as 
that  of  the  object  facing  the  mirror;  as  it  under- 
goes what  is  known  as  lateraMnyersion.  This  is 
best  understood  by  holding  a  printed  page  in  front 
of  a  plane  mirror,  when  the  words  or  letters  will 
read  from  right  to  left  (Fig.  27). 

Spheric  Mirrors.  A  spheric  mirror  is  a  portion 
of  a  reflecting  spheric  surface;  its  center  of  curva- 
ture is  therefore  the  center  of  the  sphere  of  which 
it  is  a  part.  Spheric  mirrors  are  of  two  kinds,  con- 
cave and  convex. 


.-           •* 

—  -f— 

~T  

R 
E    F 
LEG 
TION 

fl 
1    3 
03J 
HOIT 

FIG.  27. 

Reflection  from  a  Concave  Mirror  (Fig.  28). 
All  rays  of  light  that  pass  through  the  center  of 
curvature  to  a  concave  mirror  are  normals  or  per- 
pendiculars at  their  points  of  incidence;  in  other 
words,  these  rays  of  light  always  travel  back  and 
forth  on  these  same  lines.  With  this  clearly  in 
mind  the  reader  can  at  once  appreciate  the  fact  that 
each  point  on  the  surface  of  a  curved  mirror  is 
equivalent  to  a  plane  surface  and  reflects  light  ac- 


REFLECTION   FROM  A  CONCAVE   MIRROR.  53 

cording  to  the  laws  of  reflection  just  mentioned. 
Parallel  rays  are  reflected  from  a  concave  mirror  j 
and  are  brought  to  a  focus  in  front  of  it.  This 
focus  is  called  the  p£mcipal__focus  and  is  always! 
situated  at  one-half  the  distance  of  the  center  of] 
curvature.  If  the  center  of  curvature  is  at  four 
inches,  then  the  principal  focus  or  focus  for  paral- 
lel rays  will  be  at  two  inches.  If  the  center  of  cur- 
vature is  at  ten  inches,  then  the  principal  focus  will 
be  at  five  inches,  etc.  The  ray  of  light  which  passes 
through  the  center  of  curvature  and  the  principal 
focus  is  called  the  principal  axis.  All  other  rays 
which  pass  through  the  center  of  curvature  are 
called  secondary  axes.  Rays  of  light  which  di- 
verge from  some  point  between  infinity  (twenty 
feet)  and  the  center  of  curvature  will  be  reflected 
by  a  concave  mirror  and  brought  to  a  focus 
at  a  point  between  the  principal  focus  and  the 
center  of  curvature.  The  reverse  of  this  state- 
ment is  equally  true,  i.  e.,  rays  of  light  diverg- 
ing from  a  point  between  the  principal  focus 
and  the  center  of  curvature  will  converge  at 
some  point  between  the  center  of  curvature 
and  infinity.  In  other  words,  the  point  from 
which  rays  of  light  diverge  and  the  point  to 
which  they  converge  are  conjugate  points,  or  foci. 
These  points  are  "  yoked  together."  They  are  in- 
terchangeable. In  Fig.  28  if  a  point  of  light  was 
placed  at  /  its  rays  after  reflection  would  focus  at  G. 
It  has  already  been  stated  that  parallel  rays  al- 


54 


THE   OPHTHALMOSCOPE. 


ways  focus  at  the  principal  focus,  then  if  a  point  of 
light  was  placed  at  the  principal  focus,  its  rays  after 
reflection  would  pass  parallel.  Rays  of  light  which 
diverge  from  a  point  closer  to  a  concave  mirror 


X 


X 


FIG.  28. — CC,  center  of  curvature ;  2'2r2'2',  normals  or  radii  of  cur- 
vature.    /,  PF  and  i  indicate  the  principal  axis. 

than  its  principal  focus,  can  never  meet,  as  they 
are  reflected  still  more  divergently,  but  if  the  eye 
could  intercept  them  they  would  be  projected  back- 
ward to  an  imaginary  point  back  of  the  mirror; 
this  point  back  of  the  mirror  from  which  these  di- 


FIG.  29. 


vergent  rays  appeared  to  come  is  spoken  of  as  a 
--virtual  or  negative  focus  (VV  in  Fig.  28). 

Images  Formed  by  a  Concave  Mirror.     To 
find  the  position  of  an   image  as   formed  by  a 


IMAGES    FORMED    BY    A    MIRROR. 


55 


concave  mirror,  two  rays  may  be  used  to  find  each 
individual  point  of  the  image:  one  drawn  from  a 
given  point  in  the  object  to  the  mirror,  parallel  to  the 
principal  axis  and  reflected  through  the  principal  fo- 
cus (Fig.  29) ;  the  other  ray  must  be  a  secondary 
axis  from  the  same  point,  passing  through  the  cen- 
ter of  curvature.  The  place  at  which  the  secondary 
axis  or  ray  and  the  reflected  ray  (or  their  pro- 
jections) intersect  will  give  the  position  of  the 
point  in  the  image  which  corresponds  to  the  given 
point  in  the  object.  When  finding  the  position  of 


FIG.  30. 


an  image,  if  the  extreme  points  are  found,  then 
the  intermediate  points  must  coincide.  Unlike  the 
plane  mirror,  which  produces  images  at  all  times 
and  all  distances,  the  concave  mirror  produces 
either  an  erect  and  virtual  image  if  the  object  is 
closer  than  the  principal  focus,  or  a  real  and  in- 
verted image  if  the  object  is  placed  beyond  the 
principal  focus.  If  an  object  is  at  the  principal 
focus,  then  there  will  not  be  any  image  as  the  rays 
would  be  reflected  parallel.  Fig.  29  shows  an  erect, 
virtual  image  (ar)  of  AR  which  is  closer  than  the 


THE    OPHTHALMOSCOPE. 


I  principal  focus.  Fig.  30  shows  an  inverted  but 
real  image  (ar)  of  AR  which  is  placed  beyond  the 
principal  focus.  When  an  object  is  situated  at  the 
center  of  curvature  its  image  is  equally  distant  and 
of  the  same  size,  but  inverted. 

Reflection  from  a  Convex  Mirror.  All  rays  are 
reflected  divergently  from  a  convex  mirror,  and 
parallel  rays  diverge  as  if  they  came  from  the 
principal  focus  situated  behind  the  mirror  at  a  dis- 
tance equal  to  one-half  its  radius  of  curvature. 

(  The  principal  focus  of  a  convex  mirror  is  negative. 

I  The  foci  of  convex  mirrors  are  virtual. 

Images  Formed  by  Convex  Mirrors.  These 
are  always  virtual,  erect  and  smaller  than  the  ob- 
ject. A  good  illustration  of  a  strong  convex  mir- 
ror is  the  human  cornea  which  the  student  may 


\ 


C.( 


FIG.  31. 

observe  in  any  patient  or  in  his  own  eye.  The 
closer  the  object,  the  larger  the  image,  and  the 
more  distant  the  object,  the  smaller  the  image.  In 
Fig.  31  parallel  rays  from  the  object  AR  are  re- 
flected from  the  mirror  as  if  they  came  from  the 


REFRACTION.  57 


: 


principal  focus  situated  at  half  the  distance  of  the 
center  of  curvature  CC.  Lines  drawn  from  th 
extremes  of  the  object  to  CC  are  secondary  axes, 
and  the  image  is  situated  at  the  point  of  intersec- 
tion of  the  secondary  axes  and  the  rays  from  the 
principal  focus;  and  as  these  meet  behind  the  mir- 
ror the  image  is  smaller  than  the  object,  virtual 
and  erect. 

Refraction.  From  the  Latin  "  refrangere," 
meaning  to  "  bend  back  " — i.  e.,  to  deviate  from 
a  straight  course.  Refraction  may  be  defined  as 
the  deviation  which  takes  place  in  the  direction  of 
rays  of  light  as  they  pass  from  one  medium  into 
another  of  different  density.  Or  refraction  is  said 
to  take  place  when  a  ray  of  light  passes  obliquely 
from  one  medium  to  another  and  is  so  bent  or  devi- 
ated that  its  course  in  the  second  medium  is  at  an 
angle  with  its  course  in  the  first  medium. 

Two  laws  govern  the  refraction  of  rays  of  light : 

1.  A  ray  of  light  passing  from  a  rare  into  a 
dense  medium  is  deviated  or  refracted  toward  the 
perpendicular. 

2.  A  ray  of  light  passing  from  a  dense  into  a 
rare  medium  is  deviated  or  refracted  away  from 
the  perpendicular. 

A  ray  of  light  will  continue  its  straight  course 
through  any  number  of  different  transparent  media, 
no  matter  \vhat  their  respective  densities  may  be, 
so  long  as  it  forms  right  angles  with  the  surface 
or  surfaces  (Fig.  32).  Such  a  ray  is  spoken  of  as 


THE   OPHTHALMOSCOPE. 


the  normal  or  perpendicular;  such  surfaces  are 
plane,  the  surfaces  and  perpendicular  forming  right 
angles.  Fig.  33  shows  the  perpendicular  (PP)  to 
a  piece  of  plate  glass  with  plane  surfaces.  The 


|    ICE 

< 

/  FLINT  GLASS 

I 

>   CROWN    " 

f1 

3    PLATE       '• 

^ 

> 

FIG.  32. 

ray  in  air  incident  at  O  on  the  surface  SF  is  bent 
in  the  glass  toward  the  perpendicular  PP.  The 
dotted  line  shows  the  direction  the  ray  would  have 

taken   had    it   not   been    re- 
fracted.    As  the  ray  in  the 

F   glass    comes    to   the    second 

surface  at  R  and  passes  into 
a  rarer  medium  it  is  deviated 
from  the  perpendicular  PP. 
The  ray  now  continues  its 
original  course ;  it  has  under- 
9  gone  lateral  displacement. 
Prism.  A  prism  is  any  refracting  substance 
bounded  by  plane  surfaces  which  intersect  each 
other.  The  sides  of  a  prism  are  the  inclined  sur- 
faces. The  apex  is  where  the  two  plane  surfaces 
meet. 


SPHERIC    LENSES.  59 

Prismatic  Action.  Rays  of  light  which  pass 
through  a  prism  are  always  refracted  toward  the 
base  of  the  prism  (Figs.  34  and  35).  If  an  inci- 
dent ray  is  perpendicular  to  one  surface  of  a  prism 
then  the  second  surface  alone  will  refract  the  ray, 


FIG.  34.  FIG.  35. 

but  its  direction  after  leaving  the  prism  will  be 
toward  the  base  (Fig.  34).  Prisms  do  not  form 
images.  Prisms  have  no  foci.  An  object  viewed 
through  a  prism  has  the  appearance  of  being  dis- 
placed and  in  a  direction  opposite  to  the  base,  i.  e., 
toward  the  apex. 

Lenses.  There  are  two  kinds  of  lenses  used  for 
refraction  purposes — spheres  and  cylinders. 

Spheric  Lenses.  Abbreviated  S.  or  Sph. 
Spheric  lenses  are  so  named  because  their  curved 
surfaces  are  sections  of  spheres.  A  spheric  lens  is 
one  which  refracts  rays  of  light  equally  in  all  me- 
ridians or  planes.  Spheric  lenses  are  of  two  kinds, 
convex  and  concave. 

A  convex  spheric  lens  is  thick  at  the  centre 
and  thin  at  the  edge  (Figs.  36,  37,  38).  The  fol- 
lowing are  synonymous  terms  for  convex  lenses: 


6o 


THE    OPHTHALMOSCOPE. 


(r)  plus,  (2)  positive,  (3)  collective,  (4)  mag- 
nifying. A  convex  lens  is  denoted  by  the  sign 
of  plus  (  +  ). 

Varieties  or  kinds  of  convex  lenses: 


A 


FIG.  36.  FIG.  37.  FIG.  38. 

1.  Planoconvex,  meaning  one  surface  flat  and 
the  other  convex.    It  is  a  section  of  a  sphere  (Fig. 
36). 

2.  Biconvex,  also  called  convexoconvex  or  bi- 
spheric,  for  the  reason  that  it  is  equal  to  two  plano- 
convex lenses  with  their  plane  surfaces  together 
(Fig.  37). 

3.  Concavoconvex.     This  lens  has  one  surface 
concave  and  the  other  convex,  the  convex  surface 
having  the  shorter  radius  of  curvature  (Fig.  38). 
The  following  are  synonymous  terms  for  a  con- 
cavoconvex  lens:  (i)  periscopic,  (2)  convex  men- 
iscus,  (3)   converging  meniscus   (meniscus  mean- 
ing a  small  moon)    (Fig.  38).     A  periscopic  lens 
enlarges  the  field  of  vision,  and  is  of  especial  service 
in  presbyopia.    A  periscopic  lens  is  also  spoken  of 
as  a  toric  lens. 

A  concave  spheric  lens  is  thick  at  the  edge  and 
thin  at  the  center  (Figs.  39,  40,  41).    The  follow- 


SPHERIC    LENSES. 


61 


ing  are  synonymous  terms  for  a  concave  lens :  ( I ) 

minus,  (2)  negative,  (3)  dispersive,  (4)  minifying. 

A  concave  lens  is  denoted  by  the  sign  of  minus  ( — ). 
Varieties  or  kinds  of  concave  lenses: 
i.  Planoconcave,  meaning  one  surface  flat  and 

the  other  concave  (Fig.  39). 


7      V7 


A     i\ 


FIG.  39. 


FIG.  40. 


FIG.  41. 


2.  Biconcave,  also  called  concavoconcave  or  bi- 
concave spheric,  for  the  reason  that  it  is  equal  to 
two  planoconcave  lenses  with  their  plane  surfaces 
together  (Fig.  40). 

3.  Convexoconcave.     This  lens  has  one  surface 
convex  and  the  other  concave,  the  concave  surface 
having  the  shorter  radius  of  curvature  (Fig.  41). 
The  following  are  synonymous  terms  for  a  concavo- 
convex  lens:  (i)  concave  meniscus,  (2)  diverging 
meniscus,  (3)  periscopic. 

A  spheric  lens  may  be  considered  as  made  up 
of  a  series  of  prisms  which  gradually  increase  in 
strength  from  the  center  to  the  periphery,  no  matter 
whether  the  lens  be  concave  or  convex. 

In  the  convex  sphere  the  bases  of  the  prisms  are 
toward  the  center  of  the  lens,  whereas  in  the  con- 


62 


THE   OPHTHALMOSCOPE. 


cave  the  bases  of  the  prisms  are  toward  the  edge 
(Figs.  42,  43). 


FIG.  42. 


Knowing  that  a  prism  refracts  rays  of  light 
toward  its  base,  it  may  be  stated  as  a  rule  that 
every  lens  bends  rays  of  light  more  sharply  as  the 


FIG.  43. 


periphery  is  approached,  i.  e.,  at  the  periphery  the 
strongest  prismatic  effect  takes  place. 

Parallel  rays  of  light  passing  through  a  convex 


CONJUGATE    FOCI.  63 

lens  come  together  at  a  point  called  the  principal 
focus  (Fig.  44).  This  principal  focus  is  also  known 
as  the  shortest  focus.  Parallel  rays  of  light  passing 
through  a  concave  lens  diverge,  as  if  they  came 
from  a  point  on  the  same  side  of  the  lens  as  the 
parallel  rays,  and  this  point  is  known  as  the  princi- 
pal focus  of  the  concave  lens  (Fig.  45). 


FIG.  44. 

The  action  of  a  convex  lens  is  similar  to  that  of 
a  concave  mirror,  and  the  action  of  a  concave  lens 
is  similar  to  that  of  a  convex  mirror. 


P.P. 


FIG.  45. 

Conjugate  Foci.  Lenses  like  mirrors  have  con- 
jugate foci,  conjugate  meaning  "  yoked  together." 
The  point  from  which  rays  of  light  diverge  and  the 
point  to  which  they  converge  are  conjugate  foci  or 
points;  for  instance  in  Fig.  46  the  rays  diverging 


64  THE   OPHTHALMOSCOPE. 

from  A  and  passing  through  the  lens  converge  to 
the  point  B,  then  the  points  A  and  B  are  conjugate 
foci.  They  are  interchangeable,  for  if  rays  diverge 
from  B  they  will  follow  the  same  path  back 
again  and  meet  at  A.  The  path  of  the  ray 


FIG.  46. 


CC'  is  the  same  whether  it  passes  from  A  .to 
B  or  from  B  to  A — there  is  no  difference.  It  is  by 
the  affinity  of  these  points  for  each  other,  with  re- 
spect to  their  positions,  that  they  are  called  con- 
jugate. The  equivalent  to  conjugate  foci  is  found 
in  the  long  or  myopic  eye,  an  eye  in  other  words, 
which  has  its  fovea  situated  further  back  than  the 
principal  focus  of  its  dioptric  media,  the  result  be- 
ing that  rays  of  light  from  the  fovea  of  such  an 
eye  will  be  projected  convergently  after  passing  out 
of  the  eye  and  will  meet  at  some  point  inside  of 
infinity  (twenty  feet).  The  fovea  of  a  myopic 
eye  represents  a  conjugate  focus.  A  myopic  eye 
is  in  a  condition  to  receive  divergent  rays  of  light 
at  a  focus  on  its  retina  and  to  ^grnit  convergent 
rays. 

Ordinary  Foci.  When  rays  of  light  diverge 
from  some  point  inside  of  infinity  and  beyond  the 
principal  focus,  they  will  be  brought  to  a  focus  at 
some  point  on  the  other  side  of  a  convex  lens  beyond 


ORDINARY    FOCI. 


its  principal  focus;  this  point  is  called  a  conjugate 
or  ordinary  focus.     A  lens  may  have  many  foci 
but  only  two  principal  foci.     When  rays  of  light, 
diverge  from  some  point  closer  to  a  lens  than  its 


FIG.  47. 


principal  focus,  they  do  not  converge  but  after  re- 
fraction continue  divergently,  their  focus  now  be- 
ing found  by  projecting  these  divergent  rays  back 
to  a  point  on  the  same  side  of  the  lens  from  which 
they  appear  to  come;  this  point  is  called  negative 
or  virtual  (Fig.  47).  This  is  equivalent  to  what 
takespace  in  a  short  or  hypermetropic  eye,  an 
eye  which  has  its  macula  closer  to  its  dioptric 
media  than  its  principal  focus.  In  a  state  of  rest 
the  fovea  of  such  an  eye  would  project  divergent 


FIG.  48. 


rays  outward  and  would  be  in  a  position  to  receive 
only  convergent  rays  of  light  at  a  focus  upon  its 
fovea. 
7 


66 


THE   OPHTHALMOSCOPE. 


Images  Formed  by  Lenses.  An  image  formed 
by  a  lens  is  composed  of  foci,  each  one  of  which 
corresponds  to  a  point  in  the  object.  Images  are 
of  two  kinds,  real  and  virtual. 

A  Real  Image.  This  is  an  image  formed  by 
the  actual  meeting  of  rays  of  light;  such  images 
can  always  be  projected  onto  a  screen  (Fig.  48). 


FIG.  49. 

A  Virtual  Image.  This  is  one  that  is  formed 
by  the  prolongation  backwards  of  rays  of  light  to 
a  point.  Such  images  cannot  be  projected  onto  a 
screen;  such  images  can  only  be  seen  by  looking 
through  the  lens. 

.A' 


FIG.  50. 


Fig.  49  shows  the  arrow  AB  closer  to  the  bi- 
convex lens  than  its  principal  focus.  An  eye  look- 
ing through  this  lens  at  the  arrow  would  see  a 
virtual,  erect  and  magnified  image  of  the  arrow  at 


NUMERATION    OF    LENSES.  67 

A'B'.  Fig.  50,  however,  shows  the  arrow  AR  in 
front  of  a  concave  lens  and  the  eye  looking  through 
this  lens  sees  a  virtual,  erect  and  minified  image  of 
the  arrow  at  A'R'. 

Numeration  of  Lenses.  Formerly  lenses  were 
numbered  by  the  distance  of  the  principal  focus 
from  the  center  of  the  lens,  as  measured  in  English 
inches,  one  inch  being  25.4  millimeters.  The  unit 
known  as  i,  was  a  lens  that  would  focus  rays  of 
light  at  the  distance  of  one  inch.  Half  the  unit 
was  written  l/2  and  was  called  the  half  inch,  but 
this  means  that  the  lens  is  one-half  the  strength 
of  the  unit,  and  therefore  focuses  at  twice  the  dis- 
tance of  the  unit,  viz.,  at  two  inches,  and  so  the 
old  nomenclature  numbered  its  lenses  in  fractions, 
the  denominator  of  the  fraction  signifying  the  prin- 
cipal focal  distance  in  inches. 

The  present  system  of  numbering  lenses  is  by 
the  diopter  system,  abbreviated  D.  The  unit  of 
this  system  is  a  lens  that  will  form  a  principal  focus 
at  40  inches  (39.37  English  inches).  The  strength 
or  refractive  power  of  a  dioptric  lens  is  therefore 
the  inverse  of  its  focal  distance.  The  shorter  the 
focal  distance  the  stronger  the  lens.  To  find  the 
focal  distance  of  any  dioptric  lens  in  inches  or  cen- 
timeters the  number  of  diopters  expressed  must  be 
divided  into  the  unit  of  40  inches,  or  100  centi- 
meters; for  example,  a  2  D.  lens  has  a  focal  dis- 
tance of  40  divided  by  2,  equals  20  inches,  or  100 
centimeters  divided  by  2  equals  50  centimeters. 


68 


THE    OPHTHALMOSCOPE. 


Lenses  that  have  a  refractive  power  less  than  a 
unit  are  not  expressed  in  the  form  of  fractions,  but 
in  the  form  of  decimals :  for  example,  a  lens  which 
is  only  one-fourth,  one-half  or  three-fourths  the 
strength  of  the  unit  is  written  0.25,  0.50,  0.75,  re- 
spectively. 

To  change  the  old  nomenclature  or  inch  system 
of  numbering  lenses  into  diopters,  divide  the  unit 
(40  inches)  by  the  denominator  of  the  fraction, 
and  the  result  will  be  an  approximation  in  diopters ; 
for  example,  i/io  equals  40/10,  or  4  D. ;  1/20 
equals  40/20,  or  2  D. 

Cylindric  Lens.  Abbreviated  C,  c  or  Cyl.  A 
cylinder  lens  receives  its  name  from  being  a  seg- 
ment of  a  hollow  or  solid  cylinder  parallel  to  its 


FIG.  51. 


FIG.  52. 


axis  (Figs.  51  and  52).  A  cylinder  is  a  lens  which 
refracts  rays  of  light  in  one  meridian  only  and 
that  meridian  is  always  opposite  to  its  axis.  A 
cylinder  lens  has  no  one  common  focus  or  focal 
point,  but  a  line  of  foci  which  is  parallel  to  its  axis 


CYLINDRIC    LENSES. 


69 


(Fig.  53).  The  dimension  of  a  cylinder  lens  which 
is  parallel  to  the  axis  of  the  original  cylinder,  of 
which  it  is  a  part,  is  spoken  of  as  the  axis  and  is 
indicated  on  the  lens  by  a  short  diamond  scratch 
at  its  periphery,  or  by  having  a  small  portion  of 
its  surface  corresponding  to  the  axis  ground  at 


FIG.  53- 

the  edges,  or  it  may  be  marked  in  both  ways  (Fig. 
54).  Cylinders  are  of  two  kinds,  convex  and  con- 
cave. A  convex  cylinder  converges  parallel  rays 


FIG.  54. 


of  light  so  that  they  are  brought  into  a  straight  line 
which  corresponds  to  the  axis  of  the  cylinder  (Fig. 
53).  A  concave  cylinder  diverges  rays  of  light 
opposite  to  its  axis  as  if  they  had  diverged  from 


THE   OPHTHALMOSCOPE. 


a  straight  line  on  the  opposite  side  of  the  lens  (Fig. 
55). 


FIG.  55- 

Spherocylinders.  A  spherocylinder  is  a  com- 
bination of  a  sphere  and  a  cylinder,  and  is  there- 
fore a  lens  which  may  have  one  surface  ground 
with  a  spheric  curve  and  the  other  surface  cylin- 
dric.  Spherocylinders  therefore  have  two  differ- 
ent curves.  The  spheric  curve  may  be  convex 
with  the  cylinder  surface  convex,  or  the  spheric 
surface  may  be  concave  with  the  cylinder  surface 
concave,  or  the  spheric  surface  may  be  convex 
with  the  cylinder  surface  concave,  or  the  spheric 
surface  may  be  concave  with  the  cylinder  surface 
convex,  or,  as  in  the  toric  spherocylinder,  or  two 
cylinders  of  different  strengths  may  be  ground  on 
one  surface  and  a  sphere  on  the  other  surface. 

As  a  plus  sphere 
will  bring  parallel 
rays  of  light  to  a  fo- 
cus, then  such  a  lens 
(of  proper  strength) 
if  placed  in  front  of 
a  hypermetropic  eye 
(Fig.  56)  will  increase  the  refraction  of  such  an  eye 


FIG.  56. 


SPHEROCYLINDERS. 


and  bring  parallel  rays  of  light  to  a  focus  on  the 
retina  (Fig.  57),  making  the  eye  equivalent  to  what 
is  known  as  the  standard  or  emmetropic  eye  (Fig. 
58).  The  emmetropic  eye  is  an  eye  therefore  that 


FIG.  57. 


FIG.  58. 


does  not  require  any  lens  to  make  parallel  rays 
focus  upon  its  retina. 

As  a  minus  sphere  will  diverge  parallel  rays  of 
light,  then  such  a  lens  (of  proper  strength)  if 
placed  in  front  of  a  myopic  eye  (Fig.  59)  will  give 
parallel  rays  such  an  amount  of  divergence,  that 
when  they  enter  the  myopic  eye  they  will  focus  on 


FIG.  59. 


its  retina   (Fig.  60),  making  it  equivalent  to  the 
emmetropic  eye. 

Astigmatism  is  the  condition  of  an  eye  in  which 
parallel  rays  of  light  are  not  refracted  equally  in 
all  meridians,  one  meridian  refracting  stronger 


72  THE   OPHTHALMOSCOPE. 

than  the  meridian  at  right  angles,  hence  the  use  of 
a  cylinder  lens  which  refracts  rays  in  one  meridian 
only,  and  therefore  diminishes  or  weakens  the 
stronger  meridian  in  myopia  ( — cylinder)  and  in- 
creases or  strengthens  the  refraction  in  the  weaker 
meridian  in  hypermetropia  (+ cylinder). 


FIG.  60. 

Estimating  the  Refraction  of  an  Eye  with 
the  Direct  Method.  For  a  close  approximation 
of  the  patient's  refraction,  the  following  essentials 
should  have  very  careful  attention.  The  observer 
should  wear  his  own  correcting  glasses  or  make 
due  allowance  for  his  error  when  reading  the 
findings  at  the  sight-hole  of  the  ophthalmoscope. 
The  observer  must  relax  his  accommodation,  and 
if  possible  the  patient's  accommodation  should  be 
at  rest  with  a  reliable  cycloplegic  (atropin).  The 
use  of  "  drops  "  is  not  so  important  in  the  aged. 
The  ophthalmoscope  must  be  held  close  to  the  ob- 
server's and  patient's  eye.  With  these  matters 
carefully  executed,  then  the  following  statement 
of  facts  will  be  correct. 

Emmetropia.  Seeing  the  fundus  distinctly 
without  any  lens  at  the  sight-hole  of  the  ophthal- 


MYOPIA.  /3 

moscope,  means  that  parallel  rays  are  emerging 
from  the  eye  under  observation,  then  passing 
through  the  sight-hole  of  the  instrument  enter  the 
observer's  eye  and  focus  on  his  macula. 

Hypermetropia.  If  a  plus  sphere  must  be  used 
at  the  sight-hole  of  the  ophthalmoscope  to  see  the 
eye  ground  distinctly,  then  the  eye  must  be  hyper- 
metropic  and  the  amount  of  the  hypermetropia  is 
represented  by  the  strongest  plus  glass  so  employed. 
The  rays  of  light  leaving  the  hypermetropic  eye 
divergently  (Fig.  56)  cannot  focus  on  the  ob- 
server's retina  without  the  aid  of  the  plus  glass, 
or  unless  the  observer  is  myopic ;  or  accommodates, 
which  he  must  learn  not  to  do. 

Myopia.  If  a  minus  sphere  is  used  at  the  sight- 
hole  of  the  ophthalmoscope  to  give  a  clear  view 
of  the  fundus,  which  was  otherwise  indistinct,  then 
the  eye  under  observation  must  be  myopic  and  the 
amount  of  the  myopia  is  represented  by  the  strength 
of  the  weakest  minus  sphere  so  employed.  The 
rays  of  light  leaving  the  myopic  eye  convergently 
cannot  focus  on  the  observer's  retina  without  the 
aid  of  the  minus  sphere.  If  the  observer  had  been 
myopic  two  diopters  and  did  not  wear  his  glasses 
and  the  eye  under  observation  was  also  myopic 
of  the  same  amount,  then  the  lens  at  the  sight-hole 
of  the  ophthalmoscope  would  have  been  minus  four, 
the  amount  of  the  observer's  and  the  patient's  error. 
The  same  statement  of  facts  would  hold  true  if 
they  had  each  been  hypermetropic,  then  the  plus 
8 


74  THE   OPHTHALMOSCOPE. 

sphere  at  the  sight-hole  of  the  ophthalmoscope 
would  have  recorded  both  errors.  If  the  observer 
does  not  wish  to  wear  his  refractive  error,  then  he 
must  deduct  the  amount  of  his  error  from  the 
strength  of  the  lens  with  which  he  sees  the  pa- 
tient's eye  ground  distinctly. 

Astigmatism.  To  estimate  correctly  the  refrac- 
tion of  an  astigmatic  eye  with  the  ophthalmoscope 
is  not  an  easy  matter  for  the  simple  reason  that  the 
observer  cannot  always  relax  his  accommodation, 
and  furthermore  the  examination  is  limited  princi- 
pally to  focusing  the  retinal  vessels  in  different 
meridians  and  these  vessels  do  not  always  appear 
at  convenient  places  for  this  purpose.  Astigmatism 
is  the  condition  of  an  eye  in  which  there  are  two 
principal  meridians  of  different  refracting  power, 
and  these  are  usually  at  right  angles  to  each  other. 
The  observer  with  the  ophthalmoscope  must  select 
these  two  chief  meridians  for  his  observations.  It  is 
impossible  to  estimate  the  refraction  at  the  macula 
as  there  are  no  vessels  visible  at  this  point,  there- 
fore the  examinations  are  usually  made  with  ves- 
sels at  or  near  the  disc.  The  observer  focuses  a 
selected  vessel  with  the  weakest  minus  or  strongest 
plus  glass  with  which  he  can  see  it  and  makes  a  note 
of  its  direction  and  then  focuses  another  vessel  (in 
the  same  manner)  as  near  a  right  angle  position  to 
the  first  vessel  as  possible.  The  difference  in 
strength  of  these  two  lenses  is  the  amount  of  the 
astigmatism  and  represents  the  strength  of  the 


ASTIGMATISM.  75 

f  cylinder  lens  necessary  for  its  correction.  The 
observer  must  remember  when  making  estimates 
for  astigmatic  errors  that  when  he  sees  a  vessel 
distinctly  he  is  viewing  it  through  the  meridian  op- 
posite to  its  course,  i.  e.,  if  the  vessel  is  at  axis  ninety 
he  is  seeing  it  through  the  horizontal  meridian,  if 
the  vessel  is  at  axis  one  hundred  and  eighty  he  is 
seeing  it  through  the  vertical  meridian,  etc. 

Simple  Hypermetropic  Astigmatism.  With 
the  formula  -f  3.00  cyl.  axis  90  degrees,  the  oph- 
thalmoscope would  reveal  the  horizontal  vessels  seen 
without  any  glass,  emmetropic,  and  the  vertical  ves- 
sels with  a  plus  three  at  the  sight-hole. 

Simple  Myopic  Astigmatism.  With  the  for- 
mula --2.00  cyl.  axis  180  degrees,  the  ophthal- 
moscope would  reveal  the  vertical  vessels  without 
any  lens  at  the  sight-hole  (emmetropic)  and  the 
horizontal  vessels  seen  with  a  minus  two. 

Compound  Hypermetropic  Astigmatism.  With 
formula  -f-  2.00  sph.  C  +  i.oo  cyl.  axis  90  degrees. 
Vertical  vessels  will  be  seen  distinctly  with  +  3  and 
the  horizontal  vessels  with  a  +  2.  The  difference 
between  the  chief  meridians  is  +  I,  which  is  the 
cylinder  with  its  axis  at  90  degrees  and  the  +  2 
would  be  the  amount  of  the  additional  refraction 
for  all  meridians. 

Compound  Myopic  Astigmatism.  With  a  for- 
mula --  i.oo  sph.  C  —  3.00  cyl.  axis  180  degrees, 
the  vertical  vessels  will  be  seen  with  -  -  i  and 
the  horizontal  vessels  with  •  -  4.  The  differ- 


7 6  THE    OPHTHALMOSCOPE. 

ence  between  the  two  meridians  would  be  --  3.00 
cyl.  at  axis  180  degrees.  The  --i  would  be  the 
amount  of  the  additional  myopia  for  all  meridians. 

Mixed  Astigmatism.  With  the  formula  —  2.00 
sph.  C  +  5.00  cyl.  axis  90  degrees,  the  vertical  ves- 
sels would  be  seen  with  a  +  3.00  and  the  horizontal 
vessels  with  —  2.00. 

Retinoscopy.  This  is  a  method  of  estimating 
the  refraction  of  an  eye  without  viewing  the  details 
of  the  fundus  as  in  the  direct  method,  and  the  ob- 
server does  not  have  to  make  any  note  of  his  ac- 
commodation, although  the  patient's  accommoda- 
tion should  be  relaxed  and  his  pupil  widely  dilated. 
The  observer  may  sit  at  any  distance  in  front  of 
the  patient,  preferably  at  40  inches,  and  reflect  the 
light  into  the  patient's  eye  from  the  concave  mirror 
of  the  ophthalmoscope,  or  he  may  use  a  plane  mirror 
held  in  front  of  his  eye.  Gently  rotating  the  mirror 
as  the  patient  looks  towards  the  observer's  fore- 
head, the  illumination  seen  in  the  patient's  pupil  will 
appear  to  be  stationary,  not  to  move,  or  it  will  ap- 
pear to  move  as  the  mirror  is  moved  or  it  will  ap- 
pear to  move  in  the  opposite  direction  to  that  in 
which  the  mirror  is  rotated,  depending  upon  the 
kind  of  mirror  employed  and  the  variety  of  the  re- 
fractive error. 

Retinoscopy  practiced  with  the  plane  mirror  at 
40  inches : 

i.  The  faster  the  illumination  appears  to  move 
the  weaker  the  refractive  error. 


RETINOSCOPY.  77 

2.  The  slower  the  illumination  appears  to  move 
the  stronger  the  refractive  error. 

3.  The  illumination  appearing  to  be  stationary 
as  the  mirror  is  rotated,  the  refractive  error  will 
be  myopic  i  D. 

4.  The  illumination  appearing  to  move  opposite 
to  the  movement  of  the  mirror,  the  refraction  will 
be  myopic  more  than  i  D. 

5.  The  illumination  moving  with  the  movement 
of  the  mirror  after  a  +  i  D.  has  been  placed  in 
front  of  the  eye  means  that  the  eye  is  hypermetropic. 

6.  The   illumination   appearing  to  move   faster 
in  one  meridian  than  another  (usually  the  meridian 
at  right  angles)  signifies  astigmatism. 

7.  When  the  illumination  appears  as  a  band  of 
light  extending  across  the  pupil,  then  the  eye  is  as- 
tigmatic. 

Retinoscopy  practiced  with  the  concave  mirror  at 
40  inches: 

1.  The  apparent  fast  or  slow  rate  of  movement 
of  the  illumination  signifies  respectively  a  weak  or 
strong  refractive  error. 

2.  No  apparent  movement  signifies  myopia  of 
i  D. 

3.  The  illumination  appearing  to  move  with  the 
mirror  signifies  myopia  of  more  than  i  D. 

4.  The  illumination  appearing  to  move  opposite 
to  the  movement  of  the  mirror  while  a  +  i  D.  is 
in  front  of  the  eye  signifies  hypermetropia. 


78  THE   OPHTHALMOSCOPE. 

5.  The  statements  under  6  and  7  for  the  plane 
mirror  are  equally  true  for  the  concave  mirror. 
Retinoscopy  is  certainly  the  simplest,  most  exact 
and  the  easiest  method  to  learn  to  estimate  the  re- 
fraction. 


CHAPTER  III. 

ANATOMY  AND  ANOMALIES  OF  THE  EYE. 

THE  human  eye  is  shaped  like  a  sphere  except 
that  it  has  a  constriction  on  its  anterior  portion  cor- 
responding to  the  base  of  the  cornea.  The  antero- 
posterior  diameter  of  the  standard  eye  is  24.3  milli- 
meters, transversely  it  is  23.6  millimeters,  and 
vertically  23.4  millimeters.  The  eyeball  consists 
of  three  tunics  or  coats,  and  within  are  two  humors, 
aqueous  and  vitreous,  having  the  crystalline  lens 
between  them  (Fig.  61). 

The  tunics  from  without  inward  are: 

1.  The  sclera  and  cornea. 

2.  The  choroid,  iris,  and  ciliary  body. 

3.  The  retina. 

The  media  are  the  cornea,  aqueous  humor,  crys- 
talline lens  and  vitreous  humor. 

The  aqueous  humor  occupies  the  corneal  cavity 
and  lies  in  front  of  the  lens  while  the  vitreous 
humor  fills  the  cavity  of  the  sclera,  posterior  to 
the  lens. 

The  Sclera  (o-K\rjp6<s,  "hard")  or  sclerotic  coat 
(c,  Fig.  61)  is  thickest  posteriorly  (one  millimeter) 
and  diminishes  in  thickness  anteriorly  (0.4  milli- 
meter), where  it  is  reinforced  by  the  tendons  of 
the  muscles.  The  sclera  consists  of  bundles  of  fine 

79 


8o 


THE   OPHTHALMOSCOPE. 


f 


FIG.  61. — HORIZONTAL  SECTION  OF  THE  RIGHT  EYE. — (Landois.) 
a,  Cornea ;  b,  conjunctiva ;  c,  sclerotic ;  d,  anterior  chamber  contain- 
ing the  aqueous  humor ;  e,  iris ;  //',  pupil ;  g,  posterior  chamber ;  /, 
Petit's  canal ;  j,  ciliary  muscle ;  k,  corneoscleral  limit ;  f,  canal  of 
Schlemm ;  m,  choroid ;  n,  retina ;  o,  vitreous  humor ;  No,  optic  nerve ; 
q,  nerve-sheaths ;  p,  nerve-fibers ;  Ic,  lamina  cribrosa ;  h,  crystalline 
lens ;  or,  ora  serrata ;  pc,  ciliary  processes ;  the  line,  OA,  indicates  the 
optic  axis ;  Sr,  the  axis  of  vision ;  r,  the  position  of  the  fovea  centralis ; 
Kn,  nodal  point ;  x,  equator  of  lens ;  t,  external  rectus  muscle ;  s,  inter- 
nal rectus  muscle ;  Z,  optic  nerve-sheath ;  H,  sclerotic. 


THE    CORNEA.  8  I 

fibrillse  of  connective  tissue  which  form  in  circles, 
some  corresponding  to  the  equator  and  others  run- 
ning meridionally.  The  sclera,  pearly  white  in 
color,  contains  in  its  deeper  portion  some  pig- 
ment cells.  While  the  sclera  has  very  few  vessels 
of  its  own,  yet  it  is  traversed  by  vessels  and  nerves 
which  pass  into  the  interior  of  the  eye.  The  scleral 
coat  is  anatomically  a  continuation  of  the  sheath 
of  the  optic  nerve,  which  sheath  is  itself  continuous 
with  the  dura  mater.  The  sclera,  by  virtue  of  its 
thickness,  toughness,  and  hardness,  assists  in  giv- 
ing the  eyeball  its  shape,  and  is  a  protection  to 
the  structures  within.  Posteriorly,  and  about  10 
degrees  to  the  nasal  side  of  the  center,  the  sclera 
contains  an  opening  (about  two  millimeters  in  di- 
ameter) called  the  scleral  opening  (foramen 
sclerae)  for  the  entrance  of  the  optic  nerve  fibers. 
The  scleral  coat  is  also  perforated  by  the  venae 
vorticosae  and  by  the  posterior  and  anterior  ciliary 
arteries  and  nerves. 

The  Cornea.  (/ce/>a9,  horn)  (a,  Fig.  61).  This 
structure  together  with  the  sclera,  forms  the  outer 
fibrous  tunic  or  coat  of  the  eye.  The  cornea  in 
health  represents  a  section  of  a  transparent  sphere 
with  a  radius  of  curvature,  normally  of  7.8  milli- 
meters on  its  anterior  surface.  The  posterior 
radius  of  curvature  is  about  7.^ millimeters.  These 
normal  radii  are  seldom  found  as  most  eyes  have 
corneal  astigmatism.  The  diameter  of  the  base  of 
the  cornea  is  about  12  millimeters  horizontally,  and 


82  THE   OPHTHALMOSCOPE. 

1 1  millimeters  vertically,  as  the  scleral  tissue  over- 
laps the  cornea  on  its  upper  and  lower  edges.  As 
the  diameter  of  the  eyeball  itself  is  24  millimeters 
(radius  12  millimeters),  then  the  cornea  with  its 
shorter  radius  must  adjust  itself  to  the  sclera  as  a 
watch  crystal  on  a  watch.  This  can  be  seen  with 
a  magnifying  glass  by  close  observation  of  any 
healthy  eye,  as  the  white  sclera  is  then  seen  to  ex- 
tend over  onto  the  transparent  cornea ;  this  is  usu- 
ally more  conspicuous  above  and  below,  giving  the 
cornea  the  appearance  of  a  horizontal  ellipse.  The 
cornea  is  thicker  at  its  edge  than  at  its  center.  As 
just  stated,  the  cornea  and  sclera  are  very  similar 
in  their  anatomic  construction  and  are  continuous 
structures,  though  one  is  transparent  and  the  other 
is  not;  the  cornea  has  a  different  arrangement  of 
its  fibrous  network  and  the  character  of  its  cells  is 
different  from  the  sclera  also. 

The  cornea  is  made  up  of  the  following  layers: 

1.  The  Anterior-  Epithelium.     This  consists  of 
several  layers  of  pavement  epithelium,  the  super- 
ficial are  flattened,  the  deep  cells  are  cylindrical  and 
between  these  layers   the  cells   are  more   or   less 
rounded.     This  epithelial  layer  is  virtually  a  con- 
tinuation of  the  conjunctiva  and  is    sometimes 
spoken  of  as  the  conjunctiva  of  the  cornea. 

2.  Bowman's  Membrane,  also  called  the  anterior 
elastic  membrane.     This  thin  homogeneous  mem- 
brane lies  beneath  the  epithelium;  it  is  firmly  at- 


VESSELS.  83 

tached  to  the  underlying  stroma  and  is  a  part  of  the 
cornea  proper. 

3.  The  Stroma  or  Cornea  Proper   (Substantia 
Propria).     This  represents  the  major  portion  of 
the  cornea  and  is  continuous  with  the  sclera.     It 
contains,  or  is  made  up  of,  bundles  of  fibers  of 
connective  tissue  arranged  in  lamellae.     Between 
these  lamellae  are  spaces  containing  lymph,  hence 
they  are  called  lymph  spaces,  and  are  connected  with 
each  other  by  narrow  openings  called  canals.    Nor- 
mally the  cornea  does  not  contain  blood  vessels. 

4.  Descemet's     Membrane.       Posterior-elastic 
membrane.     As  Bowman's  membrane   forms   the 
anterior  portion  of  the  cornea  proper,  so  Desce- 
met's membrane   forms  the  posterior,   and  while 
Bowman's   is   quite  intimately  adherent   to  the 
stroma,  yet  Descemet's  membrane  is  not  so.     This 
latter  is  very  dense  or  tough  and  by  virtue  of  its 
toughness  it  is  a  protection  for  the  eye  against 
penetrating  diseases  of  the  cornea.     Descemet's 
membrane  may  be  considered  as  a  part  of  the  uvea 
or  inner  tunic  of  the  eye. 

5.  The  fifth  layer  of  the  cornea,  known  as  the 
posterior  pavement  or  endothelial  layer,  .is  but  a 
single  layer  of  cells  more  or  less   flattened,   and 
these  cells,  like  Descemet's  membrane,  are  a  part 
of  the  uvea,  and  with  Descemet's  membrane  pre- 
vent the  aqueous  fluid  from  passing  into  the  stroma. 

Vessels.     The  cornea  in  health  is  non-vascular. 
It  receives  its  nutrition  from  the  anterior  ciliary 


84  THE   OPHTHALMOSCOPE. 

vessels  which  form  a  network  of  loops  at  the  mar- 
gin (limbus)  of  the  cornea.  Plasma  passes  from 
the  loops  of  the  vessels  into  the  lymph  spaces 
or  canals  in  the  cornea,  and  in  this  way  the  cor- 
nea is  nourished. 

Nerves.  The  epithelial  cells,  Bowman's  mem- 
brane and  anterior  lamellae  of  the  cornea  proper, 
contain  numerous  fine  nerves,  branches  from  the 
long  ciliary  and  nerves  of  the  ocular  conjunctiva. 
Minute  branches  perforate  Bowman's  membrane 
from  the  stroma  and  pass  freely  to  the  epithelial 
layer.  This  network  of  nerves  acts  as  a  protec- 
tion to  the  cornea,  by  giving  it  extreme  sensibility 
to  all  external  injurious  influences.  The  cornea 
being  transparent,  and  a  section  of  a  small  sphere, 
refracts  the  rays  of  light  as  they  enter  the  eye  and 
with  the  assistance  of  the  crystalline  lens  brings 
parallel  rays  to  a  focus  at  the  macula  in  a  standard 
eye.  In  fact,  the  cornea  is  the  most  important  re- 
fractive media  of  the  eye. 

The  middle  tunic  of  the  eye  consists  of  the 
choroid,  iris  and  ciliary  body  (commonly  called 
the  uveal  tract). 

The  Choroid.  (xopioeiS^s ;  Latin  "  corium," 
skin)  (m,  Fig.  61).  The  choroid  is  known  as  the 
vascular  coat,  is  brown  in  color  and  lies  between 
the  sclera  and  the  retina,  and  extends  from  the 
edge  of  the  optic  nerve  posteriorly  w7here  it  is  0.16 
millimeter  in  thickness,  to  the  ora  serrata  (or.  Fig. 
6 1 )  anteriorly,  where  it  is  0.08  millimeter  in  thick- 


THE    CHOROID.  85 

ness.  It  has  a  few  attachments  to  the  sclera  by  the 
lamina  fusca.  Posteriorly  it  is  perforated  by  a 
round  opening  known  as  the  foramen  choroid, 
through  which  pass  the  optic  nerve  fibers  and  ves- 
sels. The  choroid  has  two  principal  attachments; 
at  the  margin  of  the  optic  nerve  entrance  (the 
region  of  the  posterior  ciliary  arteries)  and  at  the 
equator  of  the  eye,  where  most  of  the  venous  blood 
passes  out  of  the  eye  (venae  vorticosse).  Anatomic- 
ally the  choroid  is  made  up  of  five  layers. 

1.  Externally  and  next  to  the  sclera  a  layer 
known  as  the  suprachoroid,  which  is  rich  in  pig- 
ment. 

2.  The  inner  layer,  lamina  vitrea,  not  pigmented, 
lies  next  to  the  retina.     Between  the  suprachoroid 
and  the  lamina  vitria  are  three  layers  of  vessels; 
from  without  inward  these  are:   (a)  the  layer  of 
large  vessels,   (b)  the  layer  of  medium  sized  ves- 
sels, (c)  the  layer  of  capillaries  (chorio-capillaris). 

The  layer  of  large  vessels  is  made  up  mostly  of 
large  veins  which  lie  very  close  together  and  anas- 
tomose freely;  the  spaces  between  the  vessels  are 
filled  more  or  less  with  pigment  cells.  The 
amount  of  pigment  varies  in  different  eyes,  being 
abundant  in  mulattoes  and  brunettes,  and  much 
less  so  in  blondes  and  possibly  entirely  absent  in 
albinos. 

The  layer  of  medium  size  vessels  is  not  as  thick 
as  the  layer  of  large  vessels  and  is  not  as  heavily 
pigmented.  The  capillary  layer,  as  its  name  implies, 


86  THE   OPHTHALMOSCOPE. 

is  made  up  of  capillaries,  but  of  large  caliber  and 
yet  without  pigrnented  interspaces.  The  choroidal 
circulation  and  choroidal  pigment  influence  greatly 
the  color  of  the  fundus  reflex  described  in  Chapter 
IV.  The  pigment  cells  of  the  choroid  are  branched 
and  anastomosing.  The  choroid  is  not  supplied 
with  sensory  nerves.  The  posterior  ciliary  arteries 
supply  most  of  the  blood  to  the  choroid.  The  veins 
of  the  choroid  run  nearly  parallel  to  each  other, 
but  finally  converge  into  six  or  eight  large  trunks 
(veriae^voxtieosje)  and  pierce  the  sclera  obliquely 
near  the  equator,  and  carry  the  blood  from  the 
choroid. 

The  short  ciliary  arteries  are  the  chief  supply 
of  the  choroid,  and  they  number  four  or  six  small 
vessels  or  branches  from  the  ophthalmic  artery. 
These  break  up  into  about  twenty  branches,  pierc- 
ing the  sclerotic  around  the  optic  nerve.  The 
function  of  the  choroid  by  virtue  of  its  great  vas- 
cularity  is  to  nourish  the  retina,  vitreous  and  lens 
and  to  furnish  the  visual  purple,  and  by  its  pigmen- 
tation to  make  the  interior  of  the  eye  a  dark  cham- 
ber or  camera. 

The  Iris  (rainbow-shaped).  This  forms  the 
anterior  portion  of  the  uveal  tract  and  is  described 
as  a  membranous  curtain,  disc-shaped  and  per- 
forated slightly  to  the  nasal  side  of  its  center  by 
a  round  opening  called  the  pupil;  this  opening  is 
normally  about  3^2  millimeters  in  diameter.  The 
diameter  of  the  iris  is  about  n  millimeters  and  at 


THE    IRIS.  87 

its  margin  is  attached  to  the  ciliary  body,  of  which 
it  is  anatomically  a  part.  Normally  the  pupillary 
margin  of  the  iris  is  always  in  contact  with  the 
anterior  capsule  of  the  lens,  whether  the  pupil  be 
dilated  or  contracted.  The  aqueous  humor  lies 
posterior  to  the  cornea  and  anterior  to  the  lens. 
The  iris  divides  the  aqueous  humor  into  two  parts, 
known  as  the  anterior  and  posterior  chambers,  and 
these  two  chambers  are  in  communication  through 
the  pupil.  Anatomically,  the  iris  is  made  up  of 
blood  vessels  and  a  fibrous  connective  tissue,  to- 
gether with  the  pigment  cells  and  the  sphincter  of 
the  iris.  The  endothelial  lining  membrane  of  the 
cornea  and  Descemet's  membrane  are  continuous 
onto  the  anterior  surface  of  the  iris  up  to  its 
pupillary  margin;  this  covering  of  endothelial 
cells  is  not  complete  on  the  iris  for  at  various  points 
it  is  missing,  and  at  these  points  there  are  depres- 
sions in  the  iris  stroma  called  crypts.  The  posterior 
surface  of  the  iris  is  lined  with  pigment  called  the 
retinal  pigment,  and  this  continues  well  forward 
into  the  pupillary  edge  of  the  iris,  where  it  becomes 
quite  conspicuous  in  some  eyes  and  in  some  dis- 
eases of  the  iris  and  occasionally  with  cataract. 
Lying  next  to  the  retinal  pigment  of  the  iris  is  the 
dilator  of  the  pupil;  this  is  not  muscular  tissue  but 
an  elastic  tissue  made  up  of  fibers  extending  radi- 
ally from  the  pupillary  edge  of  the  iris  to  its 
periphery.  Close  to  the  pupillary  edge  of  the  iris, 
and  within  the  iris  stroma  is  found  the  sphincter 


THE   OPHTHALMOSCOPE. 

of  the  iris;  this  is  muscular  tissue,  flat  and  about 
one  millimeter  in  width.  Viewing  the  iris  on  its 
anterior  surface  it  is  found  to  be  uneven  or  filled 
with  ridges,  elevations  and  depressions,  and  at  its 
periphery  are  seen  concentric  circles;  these  latter 
are  the  folds  made  by  the  iris  when  the  pupil  dilates. 
The  ridges  are  formed  by  blood  vessels.  The  iris 
pigment  is  of  two  kinds,  one  the  pigment  in  the  iris 
stroma,  and  the  other,  the  retinal  pigment  layer. 
The  color  of  the  iris  is  controlled  in  great  part  by 
the  amount  of  its  pigment.  The  pigment  in  the 
retinal  layer  is  always  quite  abundant,  whereas  that 
in  the  stroma  varies  considerably.  If  the  stroma 
does  not  contain  any  pigment  or  only  a  small 
amount,  then  the  retinal  pigment  layer  shows 
through  the  stroma,  giving  the  iris  a  blue  color. 
The  gray  iris  is  seen  when  the  stroma,  free  from 
pigment,  is  quite  thick.  The  dark  iris  (brown, 
hazel,  etc.)  means  that  the  stroma  contains  pig- 
ment. Blondes  usually  have  light-colored  irises  and 
mulattoes  or  brunettes  dark-colored  irises,  show- 
ing that  usually  the  pigmentation  of  the  iris  is 
consistent  with  the  eye  ground  and  body  pigmen- 
tation. 

Arteries.  The  long  posterior  ciliary  and  the 
anterior  ciliary,  and  branches  of  the  muscular 
arteries  supply  the  iris  with  blood,  forming  a  large 
circle  at  the  periphery  of  the  iris  and  a  small  circle 
near  the  pupillary  margin.  Many  arteries  pass 
radially  from  the  periphery  to  the  pupillary  edge 


CILIARY   BODY.  89 

of  the  iris.  The  direction  of  these  vessels  has  al- 
ready been  incidentally  referred  to  in  the  descrip- 
tion of  the  iris. 

Nerves.  The  iris  is  supplied  by  a  motor  branch 
from  the  third  pair  of  nerves,  and  with  sympathetic 
fibers  from  the  ciliary^ganglion.  The  iris  does  not 
contain  ganglion  cells.  The  function  of  the  iris  is 
to  control  the  amount  of  light  entering  the  eye. 

Ciliary  Body  (cilia,  "  lashes,"  and  so-called 
from  radiating  folds  seen  on  the  surface  of  the 
ciliary  body)  (/,  Fig.  61 ) .  Also  from  KVK\OS,  mean- 
ing a  circle.  The  ciliary  body  in  section  is  triangu- 
lar in  shape,  the  base  of  the  triangle  being  shorter 
than  the  sides,  which  are  about  3  millimeters  in 
length.  The  ciliary  body  lies  beneath  the  sclera  and 
just  back  of  its  junction  with  the  cornea.  A  width 
of  sclera  about  4  millimeters,  extending  back  from 
the  edge  of  the  cornea,  covers  the  ciliary  body ;  this 
width  is  called  the  pericorneal  or  dajigejv^one.  The 
outer  side  of  the  ciliary  body,  that  next  to  the  sclera, 
is  formed  by  the  ciliary  muscle  and  the  inner  side 
is  formed  by  the  ciliary  processes.  The  base  of  the 
triangle  faces  forward  toward  the  cornea  and  at 
its  center  gives  attachment  or  origin  to  the  iris. 
Near  the  apex  of  this  triangular  body,  on  its  inner 
surface,  are  the  ciliary  processes,  about  seventy  in 
number,  and  lighter  in  color  than  the  rest  of  the 
ciliary  body,  which  appears  black.  The  ciliary  body 
is  attached  to  the  scleral  corneal  junction  by  the 
ligamentum  pectinatum.  In  the  ciliary  body  next 
9 


9O  THE   OPHTHALMOSCOPE. 

to  the  sclera  is  found  the  ciliary  muscle  with  its 
many  layers  of  muscular  fibers.  The  longitudinal 
or  meridional  fibers,  known  as  the  tensor  choroidise, 
or  muscle  of  Briicke  pass  backward  to  be  inserted 
into  the  external  layers  of  the  choroid.  Lying 
beneath  the  tensor  choroidiae  fibers  and  crossing 
them  here  and  there  are  found  the  circular  or 
sphincter  fibers,  the  muscle  of  Miiller.  This  is 
called  the  compressor  lentis.  Many  other  muscular 
fibers  are  also  found  in  the  ciliary  body,  but  the 
two  just  mentioned  are  the  principal  ones  considered 
in  the  act  of  accommodation.  The  ciliary  processes 
are  covered  and  filled  in  with  pigment  and  contain 
ra  great  number  of  blood  vessels.  The  ciliary  body 
is  supplied  by  the  posterior  and  anterior  ciliary 
arteries.  Some  of  the  veins  of  the  ciliary  body  and 
all  of  those  of  the  iris  empty  eventually  into  the 
vena  vorticosse,  while  a  few  of  the  veins  from  the 
ciliary  muscle  pass  out  through  the  sclera.  The 
nerves  of  the  ciliary  body,  besides  motor  branches, 
are  many  sensory  branches  from  the  trigeminus. 

Uvea  and  Uveal  Tract.  If  the  sclera  and  cor- 
nea and  optic  nerve  can  be  removed  from  an  eye, 
then  the  remaining  choroid,  ciliary  body  and  iris 
being  exposed  show  the  pupillary  opening  anteri- 
orly, and  the  opening  for  the  optic  nerve  posteriorly. 
These  three  structures,  on  account  of  their  dark 
color,  somewhat  resemble  a  grape  (uvea),  hence 
called  the  uvea  or  uveal  tract. 

The  Retina.     (Reta,  net)    (n,  Fig.  61).     This 


THE    RETINA.  9 1 

is  the  inner  tunic  or  coat  of  the  eye,  the  end  organ 
of  the  optic  nerve.  In  health  the  retina  is  a  trans- 
parent membrane  and  is  held  in  contact  with  the 
choroid  by  the  vitreous  humor.  The  retina  is  at- 
tached at  the  optic  nerve  posteriorly  and  at  the  ora 
serrata  anteriorly ;  also  at  the  f ovea  centralis,  where 
it  adheres  slightly  to  the  choroid.  The  optic  nerve 
fibers  spread  out  in  all  directions  from  the  disc  and 
pass  through  the  layers  of  the  retina,  having  their 
terminal  endings,  the  rods  and  cones,  at  the  exter- 
nal surface  of  the  retina.  The  retina  may  be  sub- 
divided into  ten  layers,  but  the  principal  tissues  of 
which  the  retina  is  composed  are  the  nervous  and 
supporting.  The  ten  layers  of  the  retina  are : 

1.  Pigment  layer. 

2.  Layer  of  rods  and  cones. 

3.  Membrana  limitans  externa. 

4.  Outer  granular  layer. 

5.  Fiber  layer  of  Henle. 

6.  Outer  reticular  layer. 

7.  Inner  granular  layer. 

8.  Inner  reticular  layer. 

9.  Ganglion-cells  layer. 
10.  Nerve  fiber  layer. 

As  the  sclera  is  considered  a  continuation  of 
the  dura  mater,  so  the  nerve  fiber  layer  of  the 
retina  may  be  considered  an  expansion  of  the  brain. 
The  part  of  the  retina  corresponding  to  the  optic  \ 
nerve  entrance  is  known  as  the  disc,  or  nerve  head,  I 
or  papilla. 


92  THE   OPHTHALMOSCOPE. 

Pigment  Layer  of  the  Retina.  This  is  called 
the  tenth  layer  of  the  retina,  and  lies  next  to  the 
choroid.  It  is  a  most  important  layer  or  part  of  the 
retina  as  it  is  a  guide  to  the  observer  with  the 
ophthalmoscope,  and  suggests  the  separation  or 
line  of  demarkation  between  the  retinal  and  cho- 
roidal  structures  during  any  inflammation  affecting 
either  one.  The  pigment  consists  of  six-sided  cells 
and  in  a  single  layer;  the  cells  are  separated  by  a 
clear  or  transparent  space,  and  each  cell  is  pig- 
mented  to  only  one-half  its  thickness  (1/500  of  a 
line) ;  the  cell  itself  is  therefore  1/250  of  a  line  in 
thickness.  This  is  important  to  know  and  appre- 
ciate, as  it  explains  the  coloring  of  the  fundus  re- 
flex as  coming  from  the  choroid  and  not  from  the 
retina,  this  pigmentation  not  being  sufficient  in  it- 
self to  entirely  conceal  the  choroidal  reflex. 

The  Lens,  also  called  crystalline  body.  Nor- 
mally the  lens  is  without  color  and  transparent,  bi- 
convex in  shape,  with  a  longer  radius  on  the  an- 
terior than  on  the  posterior  surface,  the  former 
being  about  10  and  the  latter  6  millimeters.  The 
lens  is  held  in  place  by  its  own  ligament  (liga- 
mentum  suspensorium  lentis,  or  zonula  of  Zinn). 
The  edge  or  equator  of  the  lens  is  about  .5  milli- 
meter from  the  ciliary  processes.  At  rest  the  lens 
is  8.7  millimeters  in  its  equatorial  diameter,  and  3.6 
millimeters  in  its  anteroposterior  diameter  on  its 
axis,  from  pole  to  pole.  The  center  of  the  lens  is 
called  the  nucleus,  and  the  remaining  portion  is 


THE   LENS.  93 

called  the  cortex.  The  nucleus  of  the  lens  is  a  hard- 
ening or  sclerosis  which  begins  to  form  at  the 
center  of  the  lens  soon  after  birth,  and  gradually 
increases  until  old  age  (about  seventy  years), 
when  the  entire  lens  may  be  said  to  be  sclerosed,  or 
hardened,  or  to  become  all  nucleus.  Sclerosis  does 
not  mean  a  loss  of  transparency,  though  the  lens 
may  become  amber  colored  as  age  advances.  It  is 
this  gradual  hardening  of  the  lens  from  its  center 
to  the  periphery  that  causes  in  great  part  the  loss 
of  accommodation  which  takes  place  from  youth  to 
old  age.  The  lens  is  made  up  of  long  six-sided 
fibers  which  pass  to  and  from  the  anterior  and 
posterior  surface  of  the  lens.  These  fibers  are  held 
together  by  outward  pressure  and  also  by  a  cement 
substance  (liquor  Morgagni).  The  anatomy  of  the 
lens  may  be  described  as  made  up  of  three  primary 
sectors,  giving  it  a  Y-shape  and  these  prongs  of 
the  Y  are  still  further  branched,  making  the  Y 
something  of  a  star  figure,  called  the  "  lens  star." 
The  lens  is  surrounded  by  its  transparent  capsule. 
That  portion  of  the  capsule  on  the  anterior  surface 
is  called  the  anterior  capsule,  and  that  on  the  pos- 
terior surface  is  called  the  posterior  capsule.  The 
anterior  capsule  is  thicker  than  the  posterior  and 
has  a  layer  of  epithelial  cells  lining  its  inner  sur- 
face, and  it  is  from  these  cells  that  the  lens  fibers 
have  their  origin.  The  lens  is  without  nerves  or 
vessels  and  is  said  to  receive  its  nourishment  by 
osmosis.  The  lens  ligament  is  a  thin,  fibrous  mem- 


94  THE   OPHTHALMOSCOPE. 

brane,  having  its  origin  at  the  ciliary  body  and 
many  of  its  fibers  may  be  traced  to  the  ora  ser- 
rata.  As  these  fibers  pass  from  the  ciliary  processes 
part  of  them  adhere  to  the  anterior  capsule  and  part 
to  the  posterior,  and  some  few  to  the  capsule  at 
the  equator  of  the  lens.  The  triangular  space  at 
the  equator  of  the  lens  formed  between  the  an- 
terior and  posterior  fibers  of  the  ligament  is  called 
the  canal  of  Petit.  The  function  of  the  lens  is  to 
maintain  the  focus  at  the  macula  of  rays  of  light 
entering  the  eye  from  various  distances  at  differ- 
ent times. 

The  Vitreous  (corpus  vitreum,  meaning  a  body 
of  glass)  is  a  transparent,  colorless  substance  of  the 
consistency  in  health  of  gelatinjelly,  and  fills  the 
large  posterior  or  scleral  chamber  of  the  eye.  It 
lies  in  contact  with  the  optic  disc,  the  retina,  ciliary 
body  and  lens,  the  latter  with  its  capsule  resting 
in  a  depression  in  the  vitreous  called  the  fossa  patel- 
laris.  The  vitreous  is  made  up  of  round  and 
branched  cells,  and,  like  the  lens,  does  not  contain 
blood  vessels  or  nerves.  It  receives  its  nourishment 
from  the  choroid,  the  ciliary  body  and  vessels  of 
the  retina.  The  vitreous  is  surrounded  by  a  very 
thin,  transparent,  structureless  membrane  called  the 
lrv_aloid.  During  intra-uterine  life  the  vitreous  is 
perforated  in  its  antero-posterior  axis  by  the  hy- 
aloid artery  and  vein  which  pass  from  the  disc  to 
the  posterior  surface  of  the  lens.  These  vessels 
normally  become  absorbed  before  birth,  but  in  their 


OPTIC    NERVE.  95 

place  there  remains  a  canal  known  as  a  lymgh  chan- 
nel. Canal  of  Cloquet.  Normally  this  cannot  be 
seen  with  the  ophthalmoscope. 

Optic  Nerve.  The  nerve  is  covered  in  its  course 
from  the  optic  foramen  by  a  loose  sheath  ((jural 
sheath)  which  is  continuous  with  the  dura  mater. 
This  sheath,  as  already  stated,  is  also  continuous 
with  the  sclerotic  coat.  Immediately  surrounding 
the  nerve  is  the  gial_5li£ajh,  which  is  continuous 
with  the  pia  mater.  This  pial  sheath  sends  pro- 
longations in  between  the  bundles  of  nerve  fibers 
and  extends  as  far  forward  as  the  lamina  cribrosa. 
As  the  outer  sheath  covers  the  nerve  loosely  and 
the  pial  sheath  beneath  adheres  closely,  there  is 
left  an  intervening  space  known  as  the  intervaginal, 
containing  a  portion  of  the  arachnoid,  and  this 
space  is  continuous  posteriorly  with  the  subarach- 
noid  within  the  cranium,  but  anteriorly  at  the 
membrana  cribrosa  it  is  more  or  less  of  a  cul-de- 
sac.  The  arachnoid  membrane  contains  many  mi- 
nute openings,  and  it  is  by  means  of  these  openings 
that  the  spaces  each  side  of  the  arachnoid  are  in 
free  communication  one  with  the  other.  Each  optic 
nerve  fiber  (about  500,000  in  all)  has  its  own  indi- 
vidual sheath  (white  matter  of  Schwann)  until  it 
comes  to  the  membrana  cribrosa  (Ic,  Fig.  61),  and 
here  each  fiber  loses  its  covering  and  collectively 
these  fibers  pass  through  the  foramen  sclera  and 
go  to  assist  in  the  formation  of  the  retinal  fiber 
layer. 


96  THE   OPHTHALMOSCOPE. 

Lamina  Cribrosa  (Ic,  Fig.  61),  meaning  sieve- 
like,  is  composed  of  fibers  from  the  sclera  and  some 
from  the  pial  sheath.  These  fibers  traverse  the 
foramen  sclera  and  serve  as  a  support  to  the  intra- 
ocular contents  and  also  to  the  optic  nerve  fibers. 

Blood  Vessels.  The  posterior  ciliary  arteries 
perforate  the  scleral  coat  around  the  entrance  of 
the  optic  nerve  where  it  enters  the  sclera,  arid  these 
vessels  send  off  branches  which  anastomose  and 
form  an  arterial  circle  called  the  circle  of  Haller. 
From  this  circle  fine  twigs  pass  between  the  trans- 
parent nerve  fibers  which  lie  anterior  to  the  mem- 
brana  cribrosa,  and  they  in  turn  anastomose  with 
branches  from  the  central  vessels  of  the  nerve. 
From  this  description  the  reader  will  understand 
and  appreciate  the  circulation  which  takes  place  in 
the  nerve  head  and  that  the  vascularity  of  the  disc 
is  connected  with  the  choroidal  as  well  as  with  the 
.retinal  system  of  vessels.  The  central  artery  of 
[the  retina  is  a  branch  of  the  ophthalmic  which  comes 
[from  the  internal  carotid.  The  retinal  vein  empties 
into  the  ophthalmic  vein  and  thence  into  the  cavern- 
ous sinus. 

Optic  Disc.  The  optic  nerve  fibers  having 
dropped  their  sheaths  before  passing  through  the 
membrana  cribrosa  must  also  pass  through  a  round 
opening  in  the  choroid  (foramen  of  the  choroid) 
before  they  can  spread  out  to  form  the  fiber  layer 
of  the  retina.  The  foramen  choroid  is  a  distinct 
opening  in  the  choroid  and  this  opening  usually 


OPTIC    DISC.  97 

surrounds  these  fibers  quite  closely,  but  there  are 
many  exceptions  to  this  statement,  for  the  foramen 
choroid  may  be  quite  large  and  not  embrace  the 
fibers  closely,  or  it  may  touch  the  fibers  at  one  side 
only.  The  nerve  fibers  in  the  foramen  choroid  are 
quite  closely  bunched  together,  and  therefore  as 
they  begin  to  separate  they  must  bend  almost  at 
right  angles  over  the  edge  of  the  choroid  to  pass 
into  the  retina.  This  bunching  of  all  the  nerve 
fibers  just  where  they  bend  and  begin  to  separate 
must  form  a  prominence  or  elevation,  and  hence 
another  name  for  the  optic  nerve  head  is  papilla. 
As  the  fibers  of  the  nerve  head  are  transparent  in 
health  it  is  not  an  easy  matter  to  demonstrate  this 
elevation  with  the  ophthalmoscope,  consequently 
some  authorities  dispute  the  correctness  of  the  word 
papilla  and  state  that  the  optic  nerve  head  is  not 
elevated,  but  is  on  a  level  with  the  surrounding  eye 
ground.  It  is  at  the  disc  that  the  blood  enters  and 
leaves  the  retina.  The  disc  is  slightly  to  the  nasal 
side  of  the  posterior  pole  of  the  eye. 

The  Macula.  To  the  temporal  side  of  the  pos- 
terior pole  of  the  eye  is  found  an  area  of  most 
acute  vision  (macula  lutea)  and  at  its  center  is  a 
depression  which  is  circular  or  crescent  or  oval  in 
shape.  This  point  is  known  as  the  center  of  sight 
or  "yellow  spot,"  or  fovea  centralis;  it  is  about 
one  millimeter  in  diameter  (Plate  I.). 

Circulation  at  Macula.  The  macula  is  the  most 
vascular  part  of  the  retina.  This  is  demonstrated 

10 


98  THE    OPHTHALMOSCOPE. 

by  the  microscope,  but  the  fovea   (center  of  the 
macula)  itself  has  no  vessels^ .Plate  I.). 

While  it  has  been  stated  that  the  retina  extends 
forward  to  the  ora  serrata,  yet  some  portion  of  the 
retina  may  be  traced  forward  onto  the  ciliary  proc- 
esses and  also  onto  the  posterior  surface  of  the  iris. 
The  distance  from  the  center  of  the  disc  of  the  em- 
j  metropic  eye  to  the  macula  is  4  millimeters.  The 
thickest  part  of  the  retina  is  on  the  disc,  0.42  of  a 
millimeter;  at  the  ora  serrata  it  is  0.14  of  a  milli- 
meter, and  at  the  fovea  o.i  millimeter.  The  arteries 
of  the  retina  are  branches  of  the  central  artery  and 
can  be  traced  forward  to  the  ora  serrata,  but  they 
are  terminal  vessels  and  do  not  anastomose.  The 
large  vessels  are  in  the  nerve  fiber  layer  beneath  the 
internal  limiting  membrane,  therefore  in  that  part 
of  the  retina  nearest  the  vitreous.  The  smaller  ves- 
sels of  the  retina  extend  as  deep  as  the  internal 
granular  layer.  The  fovea  and  external  layers  of 
the  retina  are  non-vascular  and  are  nourished  by 
plasma  from  the  chorio-capillaris.  The  circulation 
of  the  retina  is  described  in  Chapter  IV.  The  func- 
tion of  the  retina  is  to  convert  the  rays  of  light  from 
external  objects  into  nervous  stimuli.  The  macula 
differs  from  the  rest  of  the  retina  in  that  it  is  com- 
posed entirely  of  cones  closely  packed  together  and 
each  cone  is  the  terminal  of  a  single  nerve  fiber,  and 
it  is  these  cones  in  this  area  which  have  the  most 
acute  vision,  whereas  in  the  periphery  of  the  retina 
the  cones  are  not  so  numerous,  the  rods  predomi- 


CONGENITAL   ANOMALIES.  99 

nating,  and  the  retinal  fibers  have  several  terminals 
instead  of  only  one,  as  at  the  macula. 

Congenital  Anomalies. 

To  avoid  errors  in  diagnosis  the  observer  should 
be  prompt  to  recognize  variations  from  the  stan- 
dard condition  known  as  anomalies. 

Cornea.  Congenital  anomalies  of  the  cornea  are 
extremely  rare,  and  are  usually  recognized  as  opaci- 
ties. These  may  or  may  not  be  vascular.  The 
cornea  of  the  young  embryo  is  opaque  and  gradu- 
ally becomes  transparent  toward  the  time  of  birth, 
but  if  for  any  reason  this  process  is  interrupted  the 
infant  may  be  born  with  an  opacity  of  the  cornea. 
Or  if  an  ulcer  of  the  cornea  took  place  during  intra- 
uterine  life  an  opacity  may  be  recognized  soon  after 
birth.  Dermoid  tumors  are  occasionally  seen  and 
are  situated  at  the  corneo-scleral  margin. 

Microphthalmos  (small  eye),  or  an  undevel- 
oped eye,  is  occasionally  observed,  and  in  this  con- 
dition the  cornea  is  correspondingly  small. 

Sclerophthalmia  is  another  rare  congenital  con- 
dition in  which  the  sclera  encroaches  on  the  cornea, 
so  that  there  is  not  the  usual  amount  of  clear  cornea 
observed. 

Iris.  As  the  color  of  the  iris  is  so  varied  in  dif- 
ferent people  and  races  the  color  itself  cannot  be 
said  to  be  anomalous,  but  when  an  iris  is  variously 
colored  it  is  spoken  of  as  heterochromia  iridis.  Or 
if  an  eye  has  a  different  colored  iris  from  its  fellow 


IOO  THE   OPHTHALMOSCOPE. 

then  the  condition  of  the  two  eyes  is  spoken  of  as 
heterophthalmos.  Occasionally  an  iris  has  a  few 
or  many  pigment  spots  (black  or  brown)  scattered 
through  it,  and  such  an  iris  is  spoken  of  as  resem- 
bling a  leopard  or  tiger  skin,  called  spotted  or  pie- 
bald iris.  Rarely  one  or  both  eyes  may  not  have 
an  iris,  and  this  is  spoken  of  as  irideremia  or  an- 
iridia,  and  such  an  eye  will  naturally  have  defective 
vision,  and  not  unusually  it  is  nystagmic. 

Congenital  Ectropion  of  the  Uvea.  This  is  a 
rounded  mass  of  the  uveal  layer  projecting  around 
the  pupillary  edge  of  the  iris  onto  the  anterior  por- 
tion of  the  iris. 

Rarely  one  or  both  eyes  may  have  a  cleft  in  the 
iris,  and  this  is  called  a  coloboma  (/coXd^w/xa,  "  mu- 
tilation ").  This  usually  appears  in  the  lower  por- 
tion giving  the  pupil  a  shape  not  unlike  a  keyhole 
in  a  door,  and  hence  is  sometimes  called  a  "  key- 
hole "  pupil.  This  being  a  congenital  condition  it 
must  be  differentiated  from  a  coloboma  due  to  an 
iridectomy,  and  this  latter  is  usually  made  in  the 
upper  portion  of  the  iris  (an  inverted  keyhole). 
There  is  also  an  incomplete  coloboma  occasionally 
seen  not  extending  to  the  ciliary  margin.  Colo- 
boma of  the  iris  may  occur  in  one  or  both  eyes ;  if 
found  in  one  eye  it  is  usually  the  left.  Coloboma  of 
the  iris  is  occasionally  associated  with  a  similar  con- 
dition in  the  lens  and  choroid. 

Pupil.  Normally  the  pupil  lies  a  trifle  to  the 
nasal  side  of  the  center  of  the  iris,  and  while  this 


THE    PUPIL. 


101 


is  quite  difficult  to  recognize,  yet  there  is  a  con- 
genital condition  in  which  the  pupil  is  markedly 
displaced,  and  this  condition  is  promptly  detected. 
This  displacement  may  be  in  any  portion  of  the 
iris  and  is  spoken  of  as  corectopia  or  ectopia  pu- 
pillae.  Corectopia  may  affect  both  irises  symmetric- 
ally, and  it  has  been  known  as  a  family  charac- 
teristic. 

Occasionally  an  iris  is  seen  having  more  than  one 
pupil  and  this  condition  is  called  polycoria.     The 


FIG.   62. — Varieties   of   Persistent    Pupillary    Membrane.     (Wickerkie- 
wicz.1) 

additional  pupil  may  be  situated  very  near  the  nor- 
mal pupil.  Another  congenital  condition  sometimes 
observed  occupying  the  pupillary  area  is  what  is 

1  Sojous  Annual. 


102 


THE   OPHTHALMOSCOPE. 


known  as  pupillary  membrane  (Fig.  62).  This 
may  appear  as  a  few  dark  threads  or  as  a  broken 
mass  of  pigment  with  many  shreds  passing  across 
from  the  anterior  capsule  of  the  lens  in  the  pupillary 
area  and  attached  to  the  small  circle  of  the  iris. 
Capsule  pupillary  membrane  is  a  portion  of  pupil- 
lary membrane  seen  extending  from  the  iris  to  the 
anterior  capsule  of  the  lens  and  if  not  carefully  in- 
spected with  a  magnifying  lens  or  loupe,  could  be 


FIG.  63. — Various  forms  of  Opacity  of  the  Lens.  The  upper  row  as 
they  appear  by  Oblique  Illumination.  The  lower  row  as  seen  by  Trans- 
mitted Light  (Direct  Method).  By  oblique  illumination  the  opacity  is 
seen  in  its  true  color. 

i,  Anterior  polar  cataract ;  2,  posterior  polar  cataract ;  3,  lamellar 
cataract ;  4,  early  stage  of  senile  cataract ;  5,  senile  cataract  not  quite 
mature  or  ripe,  for  if  the  light  is  thrown  on  the  eye  from  the  right 
side  the  iris  casts  a  shadow  in  the  lens ;  6,  subluxation  of  the  lens. 
(Jennings.) 

mistaken  for  a  posterior  synechia.  Pupillary  mem- 
brane is  the  remnant  of  the  vascular  membrane 
which  encircles  the  lens  in  intra-uterine  life  and  fails 
to  become  absorbed  before  or  shortly  after  birth. 


CATARACT.        .  103 

Cysts  and  naevi  of  the  iris  have  been  noted  as  con- 
genital anomalies. 

Lens.  Rarely  an  eye  may  be  born  without  a 
lens  (congenital  aphakia).  Congenital  anomalies 
of  the  lens  are  usually  in  the  form  of  cataract  as 
follows : 

Anterior  Polar  Cataract  (No.  I,  Fig.  63).  At 
the  anterior  pole  of  the  lens  is  seen  a  small  white 
spot  the  size  of  a  pin  point  or  a  pin  head ;  it  usually 
involves  the  capsule  and  in  many  instances  is  pyra- 
midal in  shape  and  is  sometimes  called  pyramidal 
cataract.  This  variety  of  cataract  is  a  congenital 
condition  and  may  be  caused  by  a  perforation  of 
the  cornea  in  intra-uterine  life  or  early  infancy, 
and  may  be  associated  with  inter-pupillary  mem- 
brane. If  carefully  looked  for,  the  corneal  opacity 
may  usually  be  found. 

Posterior  Polar  Cataract  (No.  2,  Fig.  63). 
This  variety  of  opacity,  as  its  name  implies,  is  in 
the  posterior  portion  of  the  lens,  and  if  anything,  a 
trifle  to  the  nasal  side  of  the  pole.  It  is  somewhat 
star-shaped  and  has  been  called  "  stellar  cataract." 
Just  as  interpupillary  membrane  showing  on  the 
anterior  capsule  is  the  result  of  unabsorbed  blood 
vessels,  so  posterior  polar  cataract  is  said  to  be 
caused  by  a  portion  of  an  unabsorbed  vessel  wall 
at  this  point. 

Lamellar,  or  Zonular,  Cataract  (No.  3,  Fig. 
63).  As  its  name  implies,  this  is  a  variety  of  cat- 
aract characterized  by  a  layer  or  zone  of  the  lens 


IO4  THE   OPHTHALMOSCOPE. 

being  opaque  and  the  remaining  portion  clear;  in 
other  words,  the  nucleus  may  be  clear  and  also  the 
cortex,  but  the  intermediate  portion  is  opaque; 
hence  this  particular  variety  is  also  correctly  called 
perinuclear  cataract.  There  are  many  departures 
from  this  condition.  This  variety  of  cataract  is 
usually  a  condition  at  birth. 

Congenital  dislocation  of  the  lens  (No.  6,  Fig. 
63).  This  is  usually  a  partial  dislocation  and 
therefore  not  complete.  Some  portion  of  the  lens 
usually  occupies  a  part  of  the  pupillary  area.  This 
condition  is  spoken  of  as  ectopia  lentis.  The  lens 
is  usually  dislocated  upward  and  this  is  usually  a 
condition  of  both  eyes.  Coloboma  of  the  lens  is  not 
common,  but  does  occur  and  is  frequently  present 
with  coloboma  of  iris  and  choroid.  Double  colo- 
boma  of  the  lens  has  been  reported.  Carefully  ex- 
amined it  appears  to  be  a  slight  notch  in  the  edge  of 
the  lower  portion  of  the  lens,  and  sometimes  as 
much  as  one-quarter  of  its  substance. 

Lenticonus.  This  rare  anomaly  is  a  conic  con- 
dition of  the  lens  at  the  center  of  its  anterior  or 
posterior  surface,  usually  the  latter.  With  the 
retinoscope  (plane  mirror)  or  the  concave  mirror 
of  the  ophthalmoscope,  or  by  oblique  light,  this 
cone  may  be  seen,  as  it  resembles  a  drop  of  oil  at 
the  point  mentioned. 

Choroid.  The  principal  congenital  anomaly  of 
the  choroid  is  that  of  coloboma  (coloboma  cho- 
roidese),  which  usually  includes  a  corresponding 


CHOROID.  105 

section  of  the  retina,  and  it  is  not  unusual  to  have 
the  coloboma  of  the  iris  also  present.  Coloboma  of 
choroid  is  an  arrest  of  development  in  the  eye  in 
intra-uterine  life  before  the  choroidal  fissure  has 
become  closed.  This  condition  is  recognized  just  as 
hare-lip  and  cleft  palate  are  recognized,  as  congeni- 
tal anomalies,  and  occasionally  as  an  hereditary  con- 
dition. Coloboma  of  the  choroid  is  of  course  seen 
with  the  ophthalmoscope  and  is  recognized  by  its 
triangular  shape,  apex  toward  or  embracing  the 
nerve  head  and  the  base  of  the  triangle  at  the  ciliary 
processes.  The  white  sclera  shows  brilliantly 
where  the  choroid  and  retina  are  absent  and  a  few 
ciliary  vessels  are  seen  in  the  area  of  the  coloboma 
and  scattered  pigment  about  the  sharp  cut  edges  of 
the  coloboma.  If  the  coloboma  of  the  choroid  exists 
alone  the  presence  of  the  retina  is  recognized  as  a 
thin  gauzy  veil  covering  the  cleft  as  also  the  retinal 
vessels  passing  over  it.  Coloboma  of  the  choroid 
is  not  always  complete,  and  is  not  always  triangular 
in  shape.  It  may  be  round  or  oval  and  may  include 
the  nerve  head,  or  it  may  occupy  the  macula,  and  is 
then  called  a  macular  coloboma.  The  coloboma 
including  the  disc  appears  as  a  cleft  or  depression 
and  is  usually  in  the  lower  portion,  or  the  entire 
nerve  head  may  appear  abnormally  large.  The 
field  of  vision  is  cut  off,  corresponding  to  the  colo- 
boma (Chapter  VI.). 

Persistent  Hyaloid  Artery.     In  embryonic  life 
the  central  artery  of  the  retina  sends  a  branch  for- 


106  THE   OPHTHALMOSCOPE. 

ward  through  the  central  portion  of  the  vitreous, 
Canal  of  Cloquet,  to  the  posterior  surface  of  the 
lens,  and  here  it  branches  and  covers  the  lens  on 
its  posterior  as  well  as  its  anterior  surface  like  a 
net,  called  vascular  membrane.  Usually  all  these 
vessels  are  absorbed  before  the  birth  of  the  infant, 
but  if  the  main  branch  from  the  disc  to  the  lens, 
or  only  a  portion  of  it,  is  absorbed,  then  the  re- 
maining portion  is  seen  with  the  ophthalmoscope 
and  it  usually  appears  as  a  dark  gray  colored 
thread  or  band  attached  to  the  disc  and  stretching 
out  into  the  vitreous  and  moving  with  the  rotation 
of  the  eyeball.  There  are  many  variations  from 
this  usual  one  here  described  (see  pupillary  mem- 
brane, Fig.  62). 

Albinism  ( Albinismus) ,  Albino.  This  is  a 
congenital  absence  of  pigment  in  the  choroid  and 
iris.  True  albinism  is  not  often  seen,  and  most 
cases  that  are  spoken  of  as  albinism  have  some 
slight  pigmentation  in  the  iris  or  iris  and  choroid. 
The  pupil  appears  pinkish  in  color,  as  does  also  the 
iris  and  the  eye  ground.  The  choroidal  circula- 
tion is  conspicuous  with  the  ophthalmoscope.  The 
eyes  have  very  poor  vision,  glasses  are  always 
necessary,  and  usually  for  some  form  of  myopia. 
Nystagmus  is  generally  quite  conspicuous  and  the 
patient  is  usually  a  blonde. 

Opaque  Nerve  Fibers.  Medullary  sheaths. 
The  fibers  of  the  nerve  usually  drop  their  outer  or 
medullary  sheaths  (white  matter  of  Schwann)  at 


OPAQUE    NERVE    FIBERS. 

the  lamina  cribrosa.  Occasionally  in  one  eye,  rarely 
in  both  eyes,  some  of  these  sheaths  are  reinstated 
just  as  the  fibers  emerge  from  the  disc  and  are  car- 
ried into  the  surrounding  retina,  sometimes  and 
usually  for  a  short  distance  only,  but  in  rare  in- 
stances for  a  considerable  distance.  These  opaque 
fibers,  a  congenital  condition,  are  usually  seen  at 
the  upper  edge  of  the  disc  (Plate  IX.),  or  at  the 
lower  edge,  or  at  both  the  upper  and  lower  edges. 
They  are  seldom  seen  at  the  inner  or  nasal  side, 
and  some  authorities  state  that  they  are  never  seen 
at  the  temporal  side.  In  appearance  these  medul- 
lary fibers  are  glistening  white,  sometimes  bluish 
white  in  color  and  have  feathered  or  striated  edges. 
The  retinal  vessels  may  be  hidden  in  these  fibers 
and  reappear  beyond  and  also  on  the  disc.  The  be- 
ginner should  not  mistake  these  fibers  for  the  snow 
bank  of  Bright's  disease  (Plate  IV.).  These  med- 
ullary fibers  may  be  quite  extensive,  or  few  in 
number.  As  they  never  appear  at  the  macula,  cen- 
tral vision  is  unimpaired  by  them,  though  the  nor- 
mal blind  spot  may  be  enlarged  by  their  presence. 
Connective  Tissue.  This  is  occasionally  seen  to 
obscure  the  disc  in  part  or  it  may  obscure  a  vessel 
or  part  of  a  vessel  on  the  disc.  This  tissue  resem- 
bles cotton  or  wool,  it  is  never  very  extensive,  it 
is  usually  congenital,  and,  like  medullary  sheaths, 
does  no  harm  in  the  healthy  eye.  It  might  act  in- 
juriously if  papillitis  should  development  in  such 
an  eye. 


CHAPTER    IV. 

THE  NORMAL  EYE  GROUND. 

As  it  is  necessary  for  the  beginner  in  ophthal- 
moscopy  to  get  a  clear  understanding  and  picture 
of  the  interior  of  a  healthy  or  standard  eye1  before 
studying  the  pathologic  or  sick  eye,  it  is  the  pur- 
pose of  the  writer  to  describe  this  condition  mi- 
nutely and  carefully,  so  that  after  this  has  once 
been  mastered,  the  student  will  be  in  a  position  to 
appreciate  any  change  or  changes  or  departures 
from  the  standard  condition. 

The  Normal  Eye  Ground.  The  inner  surface 
of  the  posterior  two-thirds  of  the  eye  is  commonly 
spoken  of  as  the  "  fundus,"  from  the  Latin  mean- 
ing "  bottom,"  but  the  term  "  eye  ground  "  is  ap- 
plied to  the  entire  inner  surface  of  the  eye  extend- 
ing well  forward  to  the  ciliary  processes.  The 
objective  points  in  the  eye  ground  will  be  described 
individually  and  with  the  idea  of  systematizing  the 
study. 

Color  of  the  Eye  Ground.  Primarily  this  is 
due  to  the  red  reflex  from  the  choroidal  coat,  which 
by  virtue  of  its  extensive  blood  supply  and  pig- 

"  Five-sixths  of  the  art  of  ophthalmoscopy  are  contained  in  a 
knowledge  of  the  normal  eye,  the  rest  is  a  series  of  representations 
which  can  be  read  almost  at  sight." — Edward  G.  Loring,  1886. 

108 


COLOR   OF   EYE    GROUND.  109 

mentation  enters  more  extensively  into  the  pro- 
duction of  the  color  of  the  eye  ground,  the  reflex 
and  the  ophthalmoscopic  picture  than  any  other 
structure.  But  there  is  nothing  uniform  about 
the  "  reflex,"  or  color,  of  the  interior  of  the  eye, 
in  fact  it  has  already  been  stated  that  the  color  of 
the  "  reflex  "  is  controlled  by  the  clearness  or  trans- 
parency of  the  media,  by  the  refractive  condition, 
the  amount  of  pigment  in  the  tissues,  and  by  the 
size  of  the  pupil.  The  eye  of  the  albino  would 
give  a  pink  glow  to  the  eye  ground,  whereas  the 
mulatto  or  dark-haired  individual  would  very  likely 
have  a  very  dark-colored  fundus.  The  eye  ground 
is  not  colored  uniformly  throughout,  and  many 
eye  grounds  appear  much  lighter  in  color  as  the 
periphery  is  approached;  this  is  due  to  an  unequal 
distribution  of  pigment.  Speaking  generally,  the 
color  effect  of  the  eye  ground  is  spoken  of  as 
"  orange  red  "  in  most  eyes,  and  this  seems  a  fair 
description,  but  this  color  effect  may  be  altered  or 
appear  to  change  in  intensity  by  the  character  or 
kind  of  light  reflected  into  the  eye.  The  indirect 
method  gives  a  much  darker  red  effect  than  the 
direct  method.  With  these  statements  about  the 
color  of  the  eye  ground,  it  is  the  sincere  hope  of  the 
writer  that  the  student  who  looks  into  a  healthy 
eye  for  the  first  time,  will  not  feel  disappointed  be- 
cause he  does  not  obtain  the  same  color  effect  that 
has  been  impressed  upon  his  mind  or  brain  by 
studying  a  certain  colored  picture  in  an  atlas. 


I  IO 


THE    OPHTHALMOSCOPE. 


Colored  pictures  of  the  fundus  are  good  in  their 
way  as  far  as  the  execution  of  the  drawing  is  con- 
cerned, and  sometimes  true  as  regards  the  color, 


FIG.  64. — HEAD  OF  THE  OPTIC  NERVE. 

A,  Ophthalmoscopic  view :  Somewhat  to  the  inner  side  of  the  center 
of  the  papilla  the  central  artery  rises  from  below,  and  to  the  temporal 
side  of  it  rises  the  central  vein.  To  the  temporal  side  of  the  latter 
lies  the  small  physiologic  excavation  with  the  gray  stippling  of  the 
lamina  cribrosa.  The  papilla  is  encircled  by  the  light  scleral  ring  (be- 
tween c  and  d),  and  the  dark  choroidal  ring  at  d.  B,  Longitudinal  sec- 
tion through  the  head  of  the  optic  nerve:  Magnified  14  X  i.  The  trunk 
of  the  nerve  up  to  the  lamina  cribrosa  has  a  dark  color  because  it  con- 
sists of  medullated  nerve-fibers,  n,  which  have  been  stained  black  by 
Weigert's  method.  The  clear  interspaces,  se,  separating  them,  corre- 
spond to  the  septa  composed  of  connective  tissue.  The  nerve-trunk  is 
enveloped  by  the  sheath  of  pia  mater,  p,  the  arachnoid  sheath,  ar,  and 
the  sheath  of  dura  mater,  du.  There  is  a  free  interspace  remaining 
between  the  sheaths,  consisting  of  the  subdural  space,  sd,  and  the  sub- 
arachnoid  space,  sa.  Both  spaces  have  a  blind  ending  in  the  sclera  at  e. 
The  sheath  of  dura  mater  passes  into  the  external  layers,  .sa,  of  the 
sclera,  the  sheath  of  pia  mater  into  the  internal  layers,  si,  which  latter 
extend  as  the  lamina  cribrosa  transversely  across  the  course  of  the  optic 


THE    OPTIC    NERVE.  I  I  I 

but  when  the  color  effect  is  carefully  studied  it 
will  soon  become  apparent  that  many  such  pic- 
tures are  very  erroneous  and  grossly  misleading. 
It  goes  without  saying  that  faulty  impressions 
gained  from  a  poorly  colored  picture,  will  give  a 
healthy  fundus  the  appearance  of  being  hopelessly 
pathologic  by  comparison.  No  illustration,  how- 
ever exact  it  may  be,  can  ever  compete  with  the 
actual  picture  as  viewed  with  the  ophthalmoscope. 
The  Optic  Nerve.  Also  called  the  disc  (some- 
times "  disk  "),  or  nerve  head,  or  papilla,  or  intra- 
ocular end  of  the  optic  nerve  (Fig.  64  and  Plate 
I.).  The  normal  and  real  size  of  the  disc  macro- 
scopically  is  1.5  millimeters,  and  its  position  in  the 
fundus  is  about  icf_or_i20  to  the  inner  side  of  the 
posterior  pole  of  the  eye.  It  corresponds  to  what 
is  known  as  the  normal  blind  spot  in  the  field  of 
vision.  As  the  retina  has  been  described  as  the 
optic  nerve  unfolded,  the  optic  disc  may  then  be 

nerve.  The  nerve  is  represented  in  front  of  the  lamina  as  of  light 
color,  because  here  it  consists  of  non-medullated  and  hence  transparent 
nerve-fibers.  The  optic  nerve  spreads  out  upon  the  retina,  r,  in  such  a 
way  that  in  its  center  there  is  produced  a  funnel-shaped  depression,  the 
vascular  funnel,  b,  on  whose  inner  wall  the  central  artery,  a,  and  the 
central  vein,  v,  ascend.  The  choroid,  ch,  shows  a  transverse  section  of 
its  numerous  blood-vessels,  and  toward  the  retina  a  dark  line,  the  pig- 
ment epithelium ;  next  the  margin  of  the  foramen  for  the  optic  nerve, 
and  corresponding  to  the  situation  of  the  choroidal  ring,  the  choroid 
is  more  darkly  pigmented.  ci  is  a  posterior  short  ciliary  artery  which 
reaches  the  choroid  through  the  sclera.  Between  the  edge  of  the  chor- 
oid, d,  and  the  margin  of  the  head  of  the  optic  nerve,  c.  there  is  a  nar- 
row interspace  in  which  the  sclera  lies  exposed,  and  which  corresponds 
to  the  scleral  ring  visible  by  the  ophthalmoscope. — (Description  and 
figure  from  Fucks.) 


112  THE   OPHTHALMOSCOPE. 

described  as  the  part  of  the  nerve  where  the  un- 
folding begins  to  take  place.  The  disc  is  the  first 
and  chief  landmark  in  the  study  of  the  eye  ground, 
and  most  descriptions  and  examinations  of  the 
eye  ground  have  the  disc  as  the  central  point  of 
departure. 

For  purposes  of  study,  the  disc  (see  Plate  I.)  in 
most  eyes  may  be  conveniently  divided  into  three 
parts : 

1.  The  central  portion,  which  is  usually  quite 
light  in  color,  contains  the  central  vessels  with 
the  porus  opticus  (if  present),  the  physiologic  cup 
(if  present),  and  a  part  of  the  membrana  cribrosa 
(if  present).    Any  one,  or  any  two,  or  all  three  of 
these  conditions  may  be  seen  in  a  single  disc,  or 
they  may  all  be  absent. 

2.  The  margin,  one  or  two  millimeters  in  width, 
represents  the  demarkation  from  the  surrounding 
fundus.    This  margin  is  whitish  or  of  a  pale  yellow 
color. 

3.  The  space  between  the  margin  and  the  center 
is  the  intermediate  zone,  and  it  is  this  zone  that 
gives  the  disc  its  true  color  and  should  have  careful 
and  minute  consideration  at  all  times  as  bearing 
upon  an  intimate  knowledge  of  the  normal  and  the 
pathologic,  i.  e,,  atrophy  and  hyperemia,  etc.     In 
health  this  intermediate  zone  is  considered  to  be 
pink  or  yellowish  red  in  color. 

Shape  of  the  Disc.  This  varies;  it  may  be 
round,  oval  or  irregular  in  outline.  Usually  it 


PHYSIOLOGIC    CUP.  113 

appears  vertically  oval.  The  oval  shape  is  usually 
explained  by  a  refractive  error,  astigmatism.  The 
irregular  shape  may  be  explained  by  some  irregu- 
larity in  the  refractive  media,  or  it  may  be  a  con- 
genital condition.  The  disc  margin  in  health  is 
usually  quite  distinct  and  easily  recognized. 

Porus  Opticus.  The  retinal  artery  and  vein  as 
they  pass  through  the  axis  of  the  optic  nerve  are 
covered  by  a  layer  of  connective  tissue  called  a 
canal,  and  at  the  disc  this  canal  is  occasionally 
expanded  so  that  the  observer  can  see  down  into 
it;  this  is  called  the  porus  opticus.  If  this  canal 
is  not  expanded  and  the  vessels  bend  sharply  as 
they  enter  the  retina,  then  there  is  no  porus  opti- 
cus present. 

Physiologic  Cup.  At  or  near  the  center  of  the 
disc  (never  occupying  the  entire  disc)  is  often  seen 
in  health  a  depression  or  pit;  this  is  called  a  cup, 
and  being  normal  is  called  physiologic,  in  other 
words  the  "  physiologic  cup."  It  is  made  by  the 
separation  of  the  nerve  fibers  after  passing 
through  the  lamina  cribrosa.  This  is  in  contra- 
distinction to  another  depression  to  be  described 
later,  and  known  as  the  glaucoma  cup,  which  oc- 
cupies the  entire  disc  (Plate  XII.),  and  this  again 
L  distinguished  from  another  very  shallow  de- 
pression called  a  saucer  depression,  not  a  cup- 
ping. This  is  seen  in  optic  atrophy,  also  to  be 
differentiated  elsewhere  (Plate  X.).  This  physi- 
ologic cupping  may  be  shallow  (Plate  I.)  or  quite 
ii 


114  THE   OPHTHALMOSCOPE. 

deep;  it  may  have  shelving  or  abrupt  edges,  or  it 
may  be  funnel-shaped  or  conical,  or  the  nasal  side 
may  be  abrupt  or  steep  and  the  temporal  side  shelv- 
ing gradually  toward  the  edge  of  the  disc;  this 
latter  is  quite  a  common  variety.  The  diameter 
of  the  physiologic  cup  varies  in  different  eyes;  it 
may  be  one-fourth  or  one-third  or  half  the  size  of 
the  disc.  Therefore,  it  may  be  said  that  the  physi- 
ologic cup  is  not  uniform  in  all  eyes  or  in  the  same 
pair  of  eyes,  and  in  fact  it  may  not  be  present  at 
all,  or  it  may  be  seen  in  one  eye  and  not  in  the  other 
eye  of  the  same  patient.  The  vessels  on  the  disc 
naturally  keep  close  to  the  disc  and  therefore  fol- 
low its  surface,  and  if  cupping  is  present  the  ves- 
sels naturally  curve  over  its  edges  and  are  seen  at 
the  bottom  of  the  cup.  The  color  of  the  cup  is 
usually  white,  and  at  times,  by  a  certain  reflection 
of  the  light,  may  appear  glistening,  and  it  is  cer- 
tainly much  lighter  in  color  than  the  remaining 
portion  of  the  nerve.  The  depth  of  the  cup  may  be 
estimated  by  the  difference  in  the  strength  of  the 
lens  used  in  the  ophthalmoscope  to  see  the  edge  of 
the  cup,  and  the  other  lens  required  to  see  the  bot- 
tom of  the  cup,  or  the  difference  in  the  strength  of 
the  lens  used  to  focus  a  vessel  at  the  edge  of  the 
cup,  and  the  strength  of  the  other  lens  required  to 
focus  the  same  vessel  at  the  bottom  of  the  cup.  The 
difference  in  level  between  the  bottom  of  the  cup 
and  the  prevailing  eye  ground  can  be  easily  demon- 
strated by  what  is  called  the  garallax.  To  do  this 


MEMBRANA    CRIBROSA.  115 

with  the  direct  method,  the  observer  watching  the 
bottom  of  the  cup  and  then  moving  his  head  per- 
pendicular to  the  line  of  sight,  the  edge  of  the  cup- 
ping with  the  surrounding  eye  ground  will  appear 
to  move  in  the  opposite  direction.  The  bottom  of 
the  cup  will  appear  to  move  with  the  movement 
of  his  head.  Remembering  that  every  three  diop-  \ 
ters  represent  about  one  millimeter  in  depth,  then  i 
if  the  edge  of  the  cup  is  seen  without  any  lens  and 
the  bottom  of  the  cup  is  seen  with  minus  three,  the 
depth  of  that  cup  is  about  one  millimeter ;  or  if  the 
edge  of  the  cup  is  seen  with  a  plus  six  and  the 
bottom  of  the  cup  is  seen  without  any  lens  at  the 
sight-hole  of  the  ophthalmoscope,  this  would  make 
a  difference  of  six  diopters,  and  the  depth  of  the 
cup  would  therefore  be  approximately  two  milli- 
meters. 

The  Membrana  Cribrosa  (Plates  VI.  and  X.). 
At  the  bottom  of  the  cupping  or  at  a  corresponding 
point  on  the  disc,  if  there  should  not  happen  to  be 
any  cupping  present,  there  is  frequently  seen  a 
gray  stippling,  or  an  area  composed  of  little  gray 
spots  with  white  interspaces;  these  spots  represent 
openings  in  the  sclerotic  coat  for  the  passage  of 
the  transparent  optic  nerve  fibers.  The  gray  spots 
represent  the  nerve  fibers  and  the  white  network  is 
the  lamina  cribrosa  or  scleral  tissue  extending 
across  the  space  through  which  the  nerve  fibers 
enter. 

The  Scleral  Ring  (Fig.  64).     As  the  transpa- 


Il6  THE   OPHTHALMOSCOPE. 

rent  nerve  fibers  pass  from  the  disc  into  the  retina 
they  pass  over  or  through  the  foramen  choroid 
and  if  this  opening  is  large  and  its  edges  equi- 
distant from  the  entering  fibers,  naturally  the 
white  sclera  will  appear  through  the  transparent 
fibers,  giving  the  disc  the  appearance  of  being  sur- 
rounded by  a  light-colored  ring.  This  according 
to  Fuchs  and  others  is  known  as  the  scleral  ring. 
Occasionally  the  foramen  choroid  approximates 
the  nerve  fibers  on  one  side  and  this  leaves  the 
sclera  exposed  through  the  nerve  fibers  on  the 
opposite  edge,  giving  the  sclera  the  appearance  of 
a  crescent  (Plate  XL).  This  crescent  is  usually 
at  the  temporal  side.  If  the  choroidal  foramen  is 
small  and  approximates  the  nerve  fibers  on  all 
sides,  then  the  scleral  ring  or  crescent  will  be 
absent.  In  myopic  eyes  and  eyes  with  glaucoma 
there  is  frequently  seen  at  the  temporal  edge  of 
the  disc  a  white  crescent  or  this  crescent  may  con- 
tinue completely  around,  forming  a  ring;  this  is 
due  to  the  absorption  of  pigment  and  the  scleral 
tissue  appears  through  the  transparent  retina.  Ac- 
cording to  Jaeger  this  is  not  a  scleral  ring,  but  con- 
nective tissue. 

The  Choroidal  Ring.  This  may  or  may  not  be 
present  (Plate  I.),  or  may  appear  as  a  crescent; 
choroidal  crescent.  It  usually  contains  in  its  com- 
position a  great  deal  of  pigment  and  this  pigment 
may  be  very  irregular  or  possibly  there  may 
be  just  one  large  mass  of  pigment  on  one  side  of 


PLATE  I. 
NORMAL  FUNDUS  OF  LEFT  EYE  OF  A  HEALTHY  LAD. 

J.  M.  T.     Aged  10  years. 

History.  A  blonde  with  light  hair  and  pink  complexion.  Blue 
irises.  Direct  method.  Refraction  almost  emmetropic  (+0.50  D.). 
Disc  is  round,  having  light-colored  center,  distinct  margins  and 
yellowish-red  intermediate  zone.  Choroidal  ring  almost  complete 
and  slightly  more  pigmented  to  the  temporal  side.  Two  cilio-retinal 
vessels  on  the  lower  outer  edge  of  disc  passing  toward  the  macula. 
The  crescentic  fovea  centralis,  with  surrounding  blood-red  area,  is 
unusually  well  shown  and  most  typical  at  this  young  age.  Veins 
and  arteries  are  slightly  to  the  nasal  side  of  the  disc.  The  arteries 
cross  the  veins  on  the  disc,  but  in  the  periphery  the  veins  cross  the 
arteries. 


118 


PLATE    I 


Normal  Fundus 


COLOR   OF   OPTIC   DISC.  121 

the  disc;  usually  this  is  not  pathologic.  The  cho- 
roidal  ring  or  crescent  may  be  present  with  a 
scleral  ring  or  crescent,  or  it  may  be  absent  in  one 
or  both  eyes. 

Color  of  the  Optic  Disc.  This  has  been  de- 
scribed as  resembling  in  color  the  marrow  of  a 
healthy  bone,  or  the  "  pink  "  of  a  sea  shell,  etc.,  but 
this  is  not  by  any  means  a  description  that  will 
answer  in  every  case,  as  the  apparent  color  of  the 
disc  is  controlled  in  great  part  in  health  by  the 
surrounding  eye  ground,  whether  this  is  heavily 
pigmented,  as  in  the  mulatto,  or  but  slightly  so,  as 
in  the  blonde,  or  whether  there  is  an  absence  of  pig- 
ment, as  in  the  albino,  or  whether  there  is  a  physi- 
ologic cupping.  The  student  should  be  ready  to 
make  allowances  for  these  contrasts.  In  health  it 
is  the  minute  capillaries  in  the  intermediate  zone 
together  with  connective  tissue  and  nerve  fibers 
which  give  the  disc  its  "  pink  "  color  or  "  orange 
red  "  or  yellowish  cast.  These  minute  capillaries 
cannot  be  seen  with  the  ophthalmoscope.  Gener- 
ally speaking,  the  disc  is  pale  toward  the  temporal 
side  and  at  the  center,  while  the  nasal  side  is  darker. 
Plate  I.  furnishes  a  good  illustration  of  a  normal 
disc  in  its  coloring  and  shape,  etc.  The  reader 
should  observe  this  and  the  other  colored  plates  by 
artificial  light  and  not  by  day  light,  otherwise  he 
will  be  liable  to  get  a  faulty  color  impression. 

The  vessels  seen  on  the  disc  (called  central  ves- 
sels) soon  branch  and  rebranch  in  the  nerve  fiber 


122  THE   OPHTHALMOSCOPE. 

layers,  carrying  the  blood  to  and  from  the  retina, 
but  they  are  not  all  of  the  same  calibre  nor  do  they 
have  the  same  curves  or  branches  or  twinings  in 
all  eyes,  or  in  the  same  pair  of  eyes.  The  central 
retinal  artery,  a  branch  of  the  ophthalmic,  enters 
the  optic  nerve  10  or  20  millimeters  back  of  the 
eyeball  and  passes  forward  in  the  axis  of  the  nerve 
and  may  appear  upon  the  disc  as  a  single  vessel, 
or  if  it  has  branched  in  the  nerve  it  will  then  ap- 
pear as  two  vessels,  and  usually  at  the  nasal  side  of 
the  center  of  the  disc.  Approximating  the  central 
artery  on  its  temporal  side  is  the  retinal  vein  which 
may  also  be  double;  it  accompanies  the  retinal 
artery  in  the  axis  of  the  optic  nerve  and  empties 
into  the  superior  ophthalmic  vein  or  directly  into 
the  cavernous  sinus. 

Size  of  the  Vessels.  The  relative  normal  pro- 
portion in  size  between  arteries  and  veins  is  gen- 
erally recognized  as  about  two  to  three.  The  veins 
are  usually  recognized  by  their  larger  size  and 
darker  color.  The  arteries  are  lighter  in  color  and 
like  the  veins  on  and  near  the  disc  have  a  light 
streak  along  their  centers ;  this  is  due  to  the  reflec- 
tion from  the  coat  of  the  vessel.  (Some  authori- 
ties state  that  this  light  streak  is  due  to  reflection 
from  the  blood  stream  for  the  reason  that  if  the 
blood  stream  is  cut  off  the  vessel  wall  cannot  be 
seen.)  This  light  streak  (reflex  streak)  has  the 
effect  or  appearance  of  dividing  the  vessel  into  two 
red  lines.  The  veins  being  larger  than  the  arteries 


SUMMARIZED    DIFFERENCE.  123 

and  their  walls  not  being  so  tense  do  not  always 
have  the  light  streak  so  conspicuous.  The  small 
arteries  and  veins  do  not  have  the  light  streak,  and 
therefore  when  looking  at  a  small  vessel  in  the 
periphery  of  the  eye  ground  the  observer  cannot 
tell  positively  whether  it  is  a  vein  or  an  artery  un- 
til he  traces  it  toward  the  disc.  The  retinal  vessels 
do  not  anastomose. 

Summarized  Difference  between  Arteries  and 
Veins,  i.  e., 

Arteries.  Veins. 

Bright  red.  Dull  red. 

Smaller.  Larger. 

Light   streak  well  marked,  and  Light     streak     not     always     so 

continues  some  distance  along  marked,  except  on  and  close  to 

the  vessel.  the  disc. 

Course  is  usually  straight.  Course  is   sinuous   and  may  be 

tortuous. 

Pulsation  seldom  seen,  except  in  Pulsation  not  unusual  on  disc. 

disease. 

Usually  cross  over  veins.  Usually  cross  under  arteries. 

It  is  interesting  to  note  that  in  health  the  arteries 
cannot  be  seen  to  pulsate,  but  that  in  some  eyes, 
venous  pulsation  (physiologic)  may  be  seen  to 
take  place  in  one  or  more  of  the  large  veins  on  or 
near  the  disc.  The  explanation  of  the  venous  pul- 
sation is  by  the  systole  of  the  heart  filling  the 
arteries  and  making  pressure  on  the  vitreous,  and 
it  is  this  interrupted  pressure  upon  the  vitreous  that 
momentarily  compresses  the  vein  on  the  disc;  in 
other  words,  the  venous  blood  has  apparently  been 
forced  out  of  the  vein  until  after  the  systole  of  the 
heart  when  it  refills,  and  this  gives  it  the  apparent 


12 


124  THE    OPHTHALMOSCOPE. 

pulsation.  This  condition  is  not  present  in  all  eyes, 
and  when  seen  does  not  necessarily  mean  disease. 
This  pulsation  can  be  produced  and  observed  by 
making  considerable  pressure  with  the  finger  on  the 
globe  of  the  eye  that  is  being  examined.  An 
anomalous  artery  of  medium  size  is  occasionally 
seen  to  curve  over  from  the  temporal  edge  of  the 
disc  and  to  pass  toward  the  macula  (Plate  I.) ;  oc- 
casionally more  than  one  vessel  is  seen.  This  ves- 
sel has  no  connection  with  the  blood  supply  above 
described,  but  is  one  of  the  ciliary  vessels,  and  since 
it  has  appeared  in  the  retina  is  called  a  cilio-retinal 
vessel.  In  embolism,  etc.,  this  vessel  may  occa- 
sionally be  of  great  value  to  a  patient  in  preserving 
some  useful  vision.  The  retinal  arteries  and  veins 
while  possessing  many  anomalies,  and  occasionally 
a  retinal  artery  and  vein  may  be  seen  to  twine 
around  each  other,  yet  they  pursue  a  sufficiently 
regular  course  up  and  down  from  the  disc  to  be 
named  accordingly,  i.  e.,  upper  nasal  artery  and 
vein,  upper  temporal  artery  and  vein,  lower  nasal 
artery  and  vein,  lower  temporal  artery  and  vein. 
Arteries  are  seen  to  cross  veins,  and  veins  to  cross 
arteries,  but  veins  are  seldom  seen  to  cross  veins, 
and  it  is  denied  that  arteries  ever  cross  arteries. 

The  Retina.  As  the  fibers  in  the  optic  nerve, 
together  with  the  connective  tissue  which  make  up 
the  major  portion  of  the  retina,  are  transparent, 
the  retina  (anterior  to  its  epithelial  layer)  is  in 
health  said  to  be  invisible,  but  this  is  not  altogether 


THE    RETINA.  125 

true,  for  under  certain  conditions  of  light  and  po- 
sition of  the  fundus  at  an  angle,  the  retina  may  be 
recognized  as  a  thin  gauze  or  veil,  and  at  times  in 
young  subjects  (not  in  the  aged)  during  the  act  of 
accommodation  light  streaks  resembling  the  waves 
or  sheen  of  a  piece  of  silk  may  be  seen  to  pass  over 
the  retina,  called  shot  silk  retina.  The  retinal 
vessels  occupying  the  nerve  fiber  layers  mark  the 
location  of  the  retina.  These  vessels,  especially  on 
and  about  the  disc,  appear  to  be  slightly  elevated, 
and  in  the  general  eye  ground  appear  to  be  lying 
well  in  front  of  the  choroid  and  not  directly  upon 
it.  In  young  subjects  the  observer  will  at  times  see 
a  circle  about  the  macula;  this  indicates  accommo- 
dative effort  and  is  not  a  sign  of  disease.  In  some 
eyes  (usually  myopic)  the  observer  may  occasion- 
ally recognize  a  crescent-shaped  reflex  at  the  nasal 
side  of  the  disc;  this  is  called  the  "Weiss  reflex," 
and  some  authorities  claim  that  it  is  indicative  of 
progressing  myopia. 

Macula  Lutea.  The  position  of  the  macula  lutea 
in  the  fundus  is  about  two  discs  in  diameter  to  the 
temporal  side  of  the  disc  and  slightly  below  the 
horizontal  meridian,  it  is  slightly  larger  than  the 
disc.  The  macula  is  recognized  as  being  oval  in 
shape  with  its  long  diameter  horizontally,  it  is 
darker  in  color  than  the  rest  of  the  fundus  and  its 
edges  gradually  shade  into  the  color  of  the  eye 
ground.  At  the  center  of  the  macula  lutea  is  the 
fovea  centralis  (center  of  sight,  "fundus  f  ovea  " 


126  THE   OPHTHALMOSCOPE. 

or  fovea) ;  this  is  a  depression,  and  its  edges  give 
a  reflex.  It  is  very  small  and  appears  as  a  bright 
spot  one  or  two  millimeters  in  diameter.  In  many 
eyes  it  appears  as  a  tiny  crescent  (Plate  I.).  It  is 
rather  lighter  in  color  than  the  surrounding  eye 
ground.  The  macular  region  is  that  portion  of  the 
eye  ground  immediately  surrounding  the  fovea  cen- 
tralis.  The  macular  region  contains  minute  capil- 
laries, but  it  is  impossible  in  healthy  eyes  to  recog- 
nize them  with  the  ophthalmoscope.  The  beginner 
with  the  ophthalmoscope  always  has  difficulty 
in  seeing  and  studying  the  macula  unless  a  mydri- 
atic  has  been  instilled,  for  immediately  that  the 
bright  light  falls  on  this  extremely  sensitive  por- 
tion of  the  fundus  the  iris  contracts  and  the  pupil 
gets  so  small  that  it  is  almost  impossible  to  see 
into  the  eye,  and  with  this  small  pupil  comes  the 
corneal  reflex,  which  adds  to  the  difficulty  of  seeing 
the  fundus.  The  macula  can  best  be  studied  in 
subjects  less  than  twenty  years  of  age.  In  old 
people  the  macula  is  not  so  conspicuous.  For  the 
observer  to  study  the  macula,  the  pupil  should  be 
dilated  and  the  patient  told  to  look  into  the  mirror. 
The  Choroid.  This  structure  is  distinguished 
principally  by  the  character  of  its  circulation;  the 
vessels  (veins  and  arteries)  all  appear  alike,  they 
are  large,  numerous  and  flattened,  and  each  variety 
anastomoses  freely,  and  they  are  without  the  light 
streak.  Pigment  areas  between  the  vessels  are  also 
distinctive  of  this  tunic  (albinos  excepted).  The 


THE    CHOROID.  127 

retinal  vessels  always  appear  in  front  of  the  cho- 
roidal  vessels.  The  choroidal  circulation  is  best 
studied  in  the  blonde  or  albino,  and  especially  in 
the  latter  where  the  normal  pigment  between  the 
choroid  and  retina  is  absent,  and  the  vessels  appear 
red  on  a  white  background.  In  some  instances, 
however,  the  choroidal  circulation  becomes  so  con- 
spicuous that  at  times  it  is  difficult  to  study  the 
retinal  circulation  (Plate  VII.).  In  other  in- 
stances the  dark  pigmentation  of  the  choroid  is 
quite  conspicuous,  with  the  characteristic  choroidal 
vessels  giving  it  a  striped  or  tesselated  appearance, 
called  "  choroide  tigree."  The  choroidal  circula- 
tion may  be  seen  in  many  eyes  toward  the  periphery 
of  the  eye  ground.  In  many  healthy  eyes  the  cho- 
roidal circulation  cannot  be  seen,  except  a  small 
portion  well  forward  toward  the  ora  serrata. 

Differential   Diagnosis   between   Retinal   and 
Choroidal  Vessels. 

Choroidal  Vessels.  Retinal  Vessels. 

More  numerous.  Not  so  numerous. 

Larger  size.  Smaller  size. 

Close  together.  Separated. 

Nearly  parallel.  Divergent  as  they  go  toward  the 

periphery. 

Frequently  anastomose.  Do  not  anastomose. 

Do     not     diminish     in     size     at  Diminish  in  size  at  periphery. 

periphery. 

Veins    and    arteries    not    distin-  Veins    and   arteries   distinguish- 

guishable.  able. 

Central  light  streak  absent.  Central  light  streak  present. 

Flat  or  riband-like  appearance.  Cylindrical  form. 


CHAPTER   V. 

STRUCTURAL  ALTERATIONS  OR  CHANGES  IN  THE  CORNEA, 
AQUEOUS  HUMOR,  IRIS,  LENS  AND  VITREOUS  HUMOR 
WHICH  ARE  INDICATIVE  OF  DISEASE  OR  INJURY. 

The  Cornea.  Examining  the  cornea  by  the 
oblique  illumination  it  will  always,  even  in  health, 
have  more  or  less  of  a  faint  smoky  appearance, 
whereas  by  ordinary  daylight  it  appears  as  highly 
polished  and  perfectly  transparent.  This  smoky 
appearance  does  not  mean  a  want  of  transparency 
but*  is  due  to  its  anatomic  construction  of  lamellae, 
etc.,  see  description,  Chapter  III.  This  haze,  or 
smoky  appearance,  varies  with  age,  is  less  conspic- 
uous in  infancy  and  becomes  more  conspicuous  in 
the  aged.  At  any  age  it  may  be  made  conspicuous 
by  having  the  light  strike  the  cornea  very  obliquely. 
By  means  of  the  oblique  illumination  one  may  de- 
tect foreign  substances  which  have  lodged  in  or 
upon  the  cornea,  such  as  particles  of  dust,  ashes, 
cinders,  wood,  glass,  iron  and  steel  filings,  emery, 
powder  grains,  etc.  Opacities  on  the  under  sur- 
face of  the  cornea,  in  the  disease  known  as  "  Des- 
cemetitis  "  ("  aquo-capsulitis  "  or  "  serous  iritis  ") 
may  also  be  recognized,  and  ulcers,  wounds,  phlyc- 
tenules,  blood  vessels,  as  in  pannus,  and  vascular 
keratitis,  opaque  spots  (opacities)  in  the  .cornea 
proper,  arcus  senilis,  general  loss  of  transparency 

128 


THE    CORNEA.  I  29 

in  various  forms  of  keratitis,  especially  the  spe- 
cific varieties,  and  also  the  haziness  accompanying 
glaucoma,  may  also  be  recognized  if  present. 

Corneal  scars,  or  opacities,  are  described  accord- 
ing to  their  size  and  density.  A  very  faint  haziness 
of  the  corneal  surface,  affecting  a  part  or  the  en- 
tire cornea,  is  spoken  of  as  a  nubecula,  meaning 
"  a  mist,"  and  may  be  compared  to  the  appearance 
of  a  clear  glass  just  faintly  breathed  upon,  or  to 
an  atmosphere  faintly  foggy.  A  nebula  is  a  cloud, 
and  therefore,  represents  a  somewhat  greater 
density  than  a  nubecula.  A  nebula  may  also  affect 
any  part  or  the  entire  cornea.  A  macula  is  a  spot 
usually  quite  white  in  color  but  small  in  size,  the 
size  of  a  pin  head,  for  instance.  Leucoma  means  a 
milk  white  area,  and  is  usually  quite  large  and  may 
be  spoken  of  as  a  large  macula;  such  an  opacity 
can  be  seen  at  quite  a  distance  from  the  eye  and 
without  the  necessity  of  employing  oblique  light 
and  condensing  lens  to  see  it.  By  the  laity  this 
form  of  corneal  opacity  is  often  erroneously  called 
a  cataract.  An  adherent  leucoma  is  a  leucoma  hav- 
ing some  iris  tissue  bound  to  it,  the  result  usually  of 
a  perforating  wound  of  the  cornea  (an  ulcer)  or  an 
injury  whereby  the  iris  has  become  entangled  in 
the  wound.  Corneal  opacities  may  frequently  be 
seen  with  a  dimly  reflected  light,  and  this  is  ob- 
tained by  having  the  gas  flame  further  removed 
from  the  mirror  of  the  ophthalmoscope  than  for 
the  regular  distance  when  examining  the  interior 


I3O  THE   OPHTHALMOSCOPE. 

of  the  eye.  If  a  foreign  substance  on,  or  an  opacity 
in,  the  cornea  is  recognized,  its  size,  shape  and  loca- 
tion should  be  carefully  noted,  and  for  this  pur- 
pose the  cornea  is  divided  into  quadrants  by 
imaginary  lines,  so  that  an  opacity  or  foreign  sub- 
stance may  occupy  the  upper  inner,  upper  outer, 
lower  inner,  or  lower  outer,  quadrant.  The  opac- 
ity or  foreign  substance  may  be  said  to  be  at  the 
pole  of  the  cornea,  or  just  above  or  below  or  to  the 
nasal  or  temporal  side  of  the  pole  of  the  cornea,  as 
the  case  may  be.  It  may  be  described  as  being  in, 
or  on,  the  cornea  in  the  center  of  the  pupillary  area 
or  in  the  upper,  or  lower,  or  inner,  or  outer,  portion 
of  the  pupillary  area.  These  minute  descriptions 
are  of  great  importance  to  the  careful  ophthalmol- 
ogist, as  bearing  upon  a  correct  diagnosis  and  prog- 
nosis as  regards  vision  in  many  injuries  and  dis- 
eases. The  nearer  the  disease  or  injury  is  to  the 
pole  of  the  cornea,  the  more  unfavorable  the  prog- 
nosis for  good  vision.  Opacities  or  foreign  bodies 
of  the  cornea  may  be  mistaken  for  opacities  in  a 
deeper  structure,  and  it  is  the  duty  of  the  observer 
therefore  to  carefully  study  their  location.  Any 
want  of  transparency  in  any  portion  of  the  cornea 
that  occupies  the  pupillary  area  (that  portion  of  the 
cornea  corresponding  to  the  underlying  pupil),  may 
be  diagnosed  as  in  the  cornea  by  having  the  pa- 
tient turn  the  eye  slowly  in  any  given  direction, 
as  the  observer  keeps  the  light  reflected  from  the 
mirror  into  the  pupil  and  the  opacity  or  foreign 


AQUEOUS    HUMOR.  131 

| 

substance  will  move  in  the  same  direction  in  which 
the  patient  turns  the  eye.  An  opacity  in  the  pupil 
itself,  that  is,  one  occupying  the  plane  of  the  iris, 
appears  to  maintain  its  relative  position  no  matter 
in  which  direction  the  patient  turns  the  eye. 

Aqueous  Humor.  This  may  be  turbid  or 
muddy,  the  result  of  inflammatory  products  thrown 
off  by  an  inflammation  of  the  iris  or  ciliary  body, 
or  both.  Blood  in  the  anterior  chamber  (called 
hyphema)  or  pus  or  leucocytes  (called  hypopion) 
may  also  be  seen.  The  iris  adhering  in  any  part 
of  the  cornea  is  called  an  anterior  synechia,  and 
adhesion  of  the  iris  to  the  anterior  capsule  of  the 
lens  is  called  a  posterior  synechia.  Vessels  may 
be  seen  on  the  surface  of  the  cornea,  as  in  pannus 
and  phlyctenular  keratitis,  and  in  the  cornea  itself 
(interstitial  keratitis).  On  the  under  surface  of 
the  cornea  may  be  seen  small,  brownish  colored 
dots  (particles  of  lymph)  arranged  frequently  in 
the  shape  of  a  pyramid,  with  the  apex  upward 
toward  the  pole  of  the  cornea,  and  the  base  of  the 
pyramid  downward ;  this  occurs  in  the  disease  known 
as  Descemetitis.  Foreign  substances,  such  as  par- 
ticles of  iron,  glass,  powder  grains,  wood,  etc.,  may 
lodge  in  the  aqueous.  Entozoa  have  also  been  seen 
in  the  aqueous. 

The  Iris.  The  anatomy  of  the  iris  may  be 
studied  with  the  oblique  light  and  magnifying  lens 
(Fig.  17),  or,  if  there  is  inflammation  or  injury  or 
a  foreign  substance  present,  these  may  also  be  seen. 


132  THE    OPHTHALMOSCOPE. 

It  will  be  well  for  the  physician  to  make  himself 
thoroughly  acquainted  with  the  normal  iris  by 
studying  healthy  eyes  carefully  with  the  oblique 
light,  and  thus  prepare  himself  for  the  prompt  de- 
tection of  any  departures  from  the  normal,  such  as 
unusual  irregularities  or  growths,  gummata,  cysts, 
tubercles,  interpupillary  membrane  ( Fig.  62  ) ,  syne- 
chia,  causing  irregular  pupils,  displaced  pupils,  or 
polycoria.  Inflammation  of  the  iris  is  indicated  by 
a  roughening  of  the  iris,  which  gives  it  a  velvety  ap- 
pearance. The  apex  of  the  light  cone  should  be 
passed  slowly  over  the  pupil  and  the  reaction  of  the 
iris  to  this  stimulation  should  be  carefully  noted. 
An  excellent  way  to  obtain  the  iris  reaction  is  to 
use  the  5-volt  lamp  of  the  luminous  ophthalmoscope 
and  as  the  patient  fixes  the  lamp,  to  suddenly  turn 
on  the  electric  current. 

The  Lens.  To  examine  the  lens  satisfactorily 
and  as  much  of  it  as  possible,  it  is  well  to  have 
the  pupil  wide  open  and  to  do  this  it  will  be  neces- 
sary to  employ  a  mydriatic  unless  otherwise  contra- 
indicated.  The  lens  has  the  same  smoky  appear- 
ance as  that  which  characterized  the  cornea  under 
examination,  and  the  observer  must  examine  it 
carefully  not  only  by  the  oblique  illumination  but 
by  the  direct  method  before  hastening  to  make  a 
diagnosis  of  a  loss  of  transparency  of  this  struc- 
ture. Changes  noted  in  the  lens  may  be  foreign 
substances,  injuries,  anomalies,  and  any  of  the 
various  forms  of  cataract. 


OPACITIES    OF    THE    LENS.  133 

Opacities  of  the  Lens  and  Its  Capsule.     On 

the  anterior  capsule  of  the  lens  in  the  pupillary 
area  there  is  occasionally  found  one  or  more  pig- 
ment spots ;  these  pigment  spots  may  not  have  any 
particular  position  and  in  a  few  instances  they  are 
seen  to  resemble  a  crescent,  or  they  may  form  a 
broken  ring  at  the  edge  of  the  iris.  These  spots 
are  portions  of  iris  pigment,  and  the  result 
usually  of  a  previous  inflammation  of  the  iris. 
Occasionally  there  is  seen  one  or  more  fine  mem- 
branous brown  shreds,  passing  from  an  attach- 
ment to  the  anterior  capsule  of  the  lens  (over  the 
pupillary  edge  of  the  iris)  to  the  outer  circle  of  the 
iris;  this  is  called  an  interpupillary  membrane 
(Fig.  62).  Of  course  the  more  abundant  these 
shreds  and  the  more  the  anterior  pole  of  the  lens 
is  obscured,  the  more  the  vision  of  the  eye  is  im- 
paired. In  a  study  of  opacities  in  the  lens  sub- 
stance or  capsules,  it  must  be  borne  in  mind  that 
with  the  oblique  light  the  opacities  appear  more 
or  less  gray  in  color  with  surrounding  darkness, 
whereas  when  studied  with  the  reflected  light  from 
the  ophthalmoscopic  mirror,  they  appear  black 
with  a  surrounding  fundus  reflex. 

Anterior  Polar  Cataract.     See  Chapter  III. 

Posterior  Polar  Cataract.    See  Chapter  III. 

Lamellar,  or  Zonular,  Cataract.  See  Chapter 
III. 

Nuclear  Cataract  (No.  4,  Fig.  64),  is  an  opacity 
of  the  nucleus  or  center  of  the  lens. 


134  THE   OPHTHALMOSCOPE. 

Cortical   Cataract   is   the   reverse   of   nuclear, 

meaning  opacity  of  the  cortical  portion  of  the  lens. 

This  may  be  more  or  less  complete,  but  usually  it  is 

more  conspicuous  in  the  lower  inner  quadrant  of 

the  lens,  and  in  any  instance  it  is  diagnosed  with  the 

ophthalmoscope  by  seeing  dark  spicules  or  striae 

like  needles  pointing  toward  the  center  of  the  lens. 

~This  is  the  most  common  form  of  beginning  senile 

;  cataract  (No.  4,  in  Fig.  64).     Cataracts  are  also 

;  named  from  their  causes. 

Choroidal  Cataract  usually  begins  as  a  nuclear 
cataract;  it  is  brown  in  color  and  is  the  result  of 
choroidal  disease;  from  its  color  and  resemblance 
to  mahogany  wood  it  has  been  called  "  mahogany 
cataract." 

Traumatic  Cataract  is  a  cataract  caused  by 
injury. 

*In  the  so-called  Black  Cataract  the  lens  becomes 
quite  dark  in  color  from  absorption  of  or  staining 
by  pigment. 

Morgagnian  Cataract  is  an  over-ripe  cataract. 
The  cortical  substance  has  become  fluid  and  the 
nucleus  remains  hard  and  drops  to  the  lower  por- 
tion of  the  lens  capsule,  which  now  resembles  a 
bag  containing  a  milky  fluid.  The  iris  often  ap- 
pears tremulous. 

Senile  Cataract  is  the  cataract  of  old  age;  a 
better  name  would  be  hard  cataract,  or  an  opaque 
sclerosed  lens.  Whenever  partial  opacity  of  the 
lens  is  diagnosed  it  is  wise  to  study  the  whole  lens 


SUBLUXATION.  135 

carefully,  and  also  the  interior  of  the  eye,  if  the 
opacity  does  not  interfere  too  greatly  with  a  view 
of  the  eye  ground,  and  to  do  this  it  will  be  necessary 
to  dilate  the  pupil  with  a  solution  of  cocain  (Chap- 
ter I.). 

Subluxation  or  Dislocation  of  the  Lens.  If  the 
ligament  of  the  lens  becomes  relaxed  or  broken 
partially  or  completely,  the  lens  will  become  sub- 
luxated  or  dislocated;  in  the  former  instance  its 
edge  may  be  seen  in  the  pupillary  area;  if  dis- 
located by  force  the  lens  may  pass  through 
the  pupil  into  the  anterior  chamber  or  fall 
back  into  the  vitreous.  If  the  lens  is  in  the 
anterior  chamber  it  can  be  easily  recognized; 
if  in  the  vitreous  or  absent  from  the  eye,  and 
the  iris  is  not  impaired,  then  its  absence  may 
be  recognized  by  a  tremulousness  of  the  iris 
(iridodonesis).  The  iris  having  the  aqueous  in 
front  and  back  of  it  (the  lens  being  out  of  posi- 
tion) it  naturally  trembles  or  feels  the  wave  motion  \ 
when  the  eye  is  suddenly  rotated;  this  trembling 
of  the  iris  is  also  noted  in  Morgagnian  cataract. 
The  absence  of  the  lens  can  usually  be  diagnosed 
by  the  greater  depth  of  the  anterior  chamber,  and 
the  tremulous  iris  and  the  refractive  error,  as  meas- 
ured by  the  strength  of  the  glass  required  to  see 
the  fundus.  If  the  lens  has  been  dislocated  into  the 
vitreous  it  may  be  studied  in  its  new  position  with 
the  ophthalmoscope,  if  there  has  not  been  too  much 
reaction  resulting  from  irritation  caused  by  the 


136  THE   OPHTHALMOSCOPE. 

lens.  Partial  dislocation  of  the  lens,  which  brings 
the  edge  of  the  lens  into  the  pupillary  area,  may 
be  diagnosed  by  oblique  light  or  with  the  ophthal- 
moscope, the  portion  of  the  pupil  without  any  lens 
giving  a  different  refractive  estimate,  when  the 
fundus  is  observed  than  the  portion  occupied  by  the 
lens  (see  Ectopia  lentis,  Chapter  III.). 

The  Vitreous  Humor.  Changes  in  the  vitreous 
indicative  of  disease,  are  loss  of  transparency  in 
parts  (opacities)  and  diminished  consistency. 
Opacities  of  this  medium  may  be  from  degenera- 
tion of  the  substance  itself  or  from  hemorrhages 
or  exudates  thrown  off  by  the  choroid  or  retina 
or  ciliary  body  or  iris.  Opacities  of  vitreous  may 
be  caused  by  foreign  bodies.  Vitreous  opacities 
are  of  varying  shapes  and  sizes,  and  may  occupy 
any  portion  of  the  vitreous.  They  may  appear 
black,  brown  or  gray  in  color,  or  semi-transparent. 
/They  are  variously  described  by  the  patient  as 
•  looking  like  different  animals  or  fishes.  They  are 
also  spoken  of  as  "  motes  "  or  "  gnats  in  front  of 
the  sight."  These  opacities  may  be  quite  station- 
ary or  freely  mobile,  depending  greatly  upon  the 
fluidity  of  the  vitreous.  Foreign  substances,  such 
as  pieces  of  glass,  steel,  iron  filings  or  chips  of 
metal,  etc.,  entering  the  eye,  may  carry  air  into 
the  vitreous,  and  this  is  recognized  as  bubbles  look- 
ing not  unlike  bubbles  of  air  under  the  cover  slide 
in  the  field  of  the  microscope.  Foreign  substances 
reflect  light  from  their  edges,  while  air  bubbles 


VITREOUS    HUMOR. 

reflect  light  from  their  centers.  The  path  of  the 
foreign  body  as  it  passed  through  the  vitreous  is 
occasionally  recognized  as  a  gray  streak. 

Opacities  and  changes  in  the  vitreous  may  be 
studied  with  the  oblique  or  focal  illumination,  or 
with  the  light  reflected  from  the  mirror  at  several 
inches  distant  or  with  the  mirror  and  a  lens  at  the 
sight-hole  of  the  ophthalmoscope.  It  is  only  in 
rare  instances  that  the  oblique  illumination  is  used 
for  studying  vitreous  changes  and  the  ophthalmo- 
scope with  a  plus  lens  at  the  sight-hole  is  used  by 
preference.  The  lens  in  the  ophthalmoscope  which 
gives  a  clear  view  of  an  opacity  in  the  vitreous,  gives 
some  idea  as  to  its  nearness  to  either  the  disc  or  pu- 
pil, i.  e.,  if  seen  with  a  strong  lens,  say  a  +  7  D.,  the 
eye  being  emmetropic,  this  would  indicate  at  once 
that  the  opacity  was  well  forward ;  if  the  opacity  was 
seen  with  a  +  I  D.  it  would  therefore  be  well  back 
near  the  retina.  If  the  observer  is  seated  ten  or 
twelve  inches  from  the  eye  and  reflects  the  light  into 
it  and  an  opacity  is  present  and  recognized,  then  if 
the  patient  is  told  to  rotate  or  turn  his  eye  upward, 
i  the  opacity  will  appear  to  move  downward  if  the 
I  opacity  is  situated  back  of  the  plane  of  the  iris, 
but  if  the  opacity  is  in  the  cornea  or  aqueous  or  an- 
terior capsule  of  the  lens,  then  it  will  appear  to 
move  upward  as  the  eye  is  turned  upward;  in 
fact,  it  may  be  stated  as  a  rule  that  all  opacities 
lying  in  front  of  the  plane  of  the  iris  will  move  in 
whatever  direction  the  eye  is  turned  or  rotated, 


138  THE   OPHTHALMOSCOPE. 

and  those  opacities  lying  back  of  the  plane  of  the 
iris  will  appear  to  move  in  the  opposite  direction  to 
that  in  which  the  eye  is  rotated.  This  statement  of 
facts  applies  particularly  to  eyes  with  small  or  un- 
dilated  pupils,  whereas  eyes  with  large  pupils  give 
a  slight  difference  in  the  appearances,  as  the  ob- 
server is  then  able  to  see  a  trifle  further  back 
into  the  eye  and  the  center  of  rotation  appears 
beyond  the  plane  of  the  iris.  The  normal  center 


FIG.  65. — To  DETERMINE  THE   POSITION   OF  A   FIXED  OPACITY   IN   THE 

EYE. — (Jennings.) 

In  the  upper  drawing  is  shown  an  opacity  on  the  cornea  at  a,  one  on 
the  anterior  surface  of  the  lens  at  b,  and  one  on  the  posterior  surface 
at  c.  Looking  into  the  eye,  these  three  opacities  appear  as  one  black 
point  in  the  center  of  the  pupil.  If  the  patient  is  now  requested  to 
look  down,  three  black  points  appear,  c  moves  upward,  b  remains  sta- 
tionary, and  a  moves  downward. 

of  rotation  lies  back  of  the  lens  about  10  milli- 
meters from  the  disc.  However,  when  the  opacity 
lies  very  near  the  plane  of  the  iris  it  is  apparently 
so  stationary  when  the  eye  is  rotated  that  it  is  often 
necessary  to  employ  the  oblique  light  to  make  a 


CHOLESTERIN    CRYSTALS.  139 

positive  diagnosis  of  its  exact  location.  Figure  65 
explains  the  description  just  given.  New  growths 
are  occasionally  seen  in  the  vitreous,  such  as  cysts, 
proliferations  from  the  retina  (retinitis  prolifer- 
ans)  and  also  entozoa,  the  cysticercus  cellulosae  and 
filaria.  These  latter  have  been  seen  in  the  cornea, 
iris  and  lens,  but  their  most  common  location  is 
between  the  choroid  and  retina. 

Foreign  bodies  in  the  vitreous  may  be  recog- 
nized if  seen  quite  early,  but  after  a  few  hours  the 
vitreous  surrounding  them  usually  becomes  more 
or  less  cloudy.  Vitreous  opacities  when  they  move 
freely  by  slight  rotation  of  the  eye,  become  very 
annoying  to  some  patients,  and  at  times  cause  hal- 
lucinations. 

Cholesterin  Crystals  (synchysis  scintillans, 
sparkling  synchysis;  synchysis  etincelant)  are  seen 
at  times  in  the  vitreous  humor,  and  give  a  most 
beautiful  pyrotechnic  display  when  seen  with  the 
ophthalmoscope.  Each  crystal  reflects  the  light, 
giving  the  appearance  of  a  shower  of  gold.  It  is  a 
rare  condition  before  the  age  of  fifty.  There  is 
no  cure  for  this  condition.  It  may  appear  in  one 
eye  alone  or  in  both. 


CHAPTER   VI. 


VISUAL  ACUITY.    FIELD  OF  VISION.     PERIMETRY. 

IN  connection  with  the  ophthalmoscopic  findings 
of  pathologic  changes,  the  physician  should  be 
ready  to  make  a  record  of  the  visual  acuity  and  the 
field  of  vision  of  each  eye,  as  these  two  records  will 
often  aid  him  materially  in  a  correct  diagnosis  and 
prognosis. 

Visual  Acuity.  This  is  generally  understood 
and  spoken  of  as  central  or  direct  vision,  and 

the  part  of  the  retina 
concerned  is  the  fovea 
centralis.  When  an 
eye  looks  at  an  ob- 
ject and  the  image  is 
formed  at  the  fovea 
centralis,  the  eye  is 
said  to  "  fix "  the  ob- 
ject. Visuaf  acuity  may 
be  defined  as  the  see- 
ing quality  of  the  eye 
without  glasses.  The 
standard  visual  acuity  is 
the  power  of  the  eye  to 
distinguish  letters  and  characters  occupying  an 
angle  of  five  minutes.  Such  letters  and  characters 

140 


c 

E 

C    P 

C    P 

in 

0  A  L 

tn 

L  0  A 

G  Y"D  T 

V  F  H  U  A 

T  G~Y  D 

F  A  V  H  U 

L  E  C  H  D  O 
CEO  R~L  C  P  A 


D    L    O    E    C    N 
C  P  A  R'C  E  O  L 


FIG.  66. — Randall's  Test-letters. 
Block  letters  on  black  or  cream- 
colored  cards. 


VISUAL    ACUITY. 


141 


in  black  are  engraved  on  a  cream-colored  card,  or 
white  letters  on  a  black  card  are  shown  in  Figs.  66, 
67,  68.  These  cards  uniformly  illuminated  are 
placed  20  feet  (six  meters)  from  the  patient  and 
each  eye  'is  tested  separately  by  covering  its  fel- 
low. The  patient  pronounces  __ 
the  letters  or  if  illiterate  he 
tells  the  direction  in  which  the 
arms  of  the  E  are  pointed. 
f  The  lowest  line  of  letters  or 
characters  which  the  eye  can 
recognize  distinctly,  is  the  vis- 
ual acuity  of  that  eye  and  it  is 
recorded  in  the  form  of  a  frac- 
tion, the  numerator  of  the 
fraction  being  the  distance 
of  the  eye  from  the  card  and 
the  denominator  being  the  size 
of  the  letters  distinguished. 
For  the  guidance  of  the 
physician  each  line  of  letters 
or  characters,  is  marked  in 
small  roman  characters  which 
tell  him  at  once  the  dis- 
tance (in  feet  or  meters)  at  which  such  letters  or 
characters  should  be  read  by  the  standard  or  emme- 
tropic  eye.  The  standard  visual  acuity  would  be 
the  line  of  letters  marked  20  feet  or  6  meters 
which  should  be  read  with  ease  at  the  distance  of 
20  feet.  If  the  eye  cannot  see  or  recognize  the 


FIG.  67.—  Gould's  Test- 
^   Gothhjc  [ettersH  in 

white   on   a  black   card. 


III 
••• 


142  THE    OPHTHALMOSCOPE. 

top  letter  on  the  test  card  at  the  distance  of  20 
feet,  then  the  distance  must  be  shortened  by  bring- 
ing the  card  slowly  toward  the  patient  or  letting 
the  patient  approach  the  card  un- 
•  B  I  til  he  is  able  to  recognize  the  letter 

S  j>L  1  distinctly. 

Peripheral  Vision.  This  is 
known  and  spoken  of  as  indirect 
vision  or  the  visual  field,  and  the 

part  or  parts  of  the  retina  con- 
^~    III     ™H  • 

&    ***    l3        cerned    lie    more    or    less    remote 

E  3  UJ  n       from    the    fovea    centralis.      The 

fovea     centralis     represents     the 
u  3  E  m  m 

most  acute  vision  and  peripheral 

u  m  E  u  3  E 

«»•••«•  or    indirect    vision    is    much    less 

FIG.  68.— illiterate     acute  and  therefore  not  so  easily 

Card.  obtained   as   the   direct.      Indirect 

vision  diminishes  or  becomes  much 

more  indistinct  as  the  outermost  limits  of  the  retina 

are  brought  into  use. 

To  Test  Peripheral  or  Indirect  Vision.  Each 
eye  must  be  examined  separately  as  in  testing  cen- 
tral or  direct  vision,  i.  e.,  keeping  the  eye  covered 
which  is  not  being  tested.  Testing  peripheral 
vision  is  known  as  perimetry,  and  an  instrument 
known  as  the  perimeter  is  generally  employed  for 
exact  work  (Fig.  69).  With  this  instrument  on 
a  convenient  table  and  the  patient  comfortably 
seated,  his  chin  is  placed  on  a  rest  and  the  eye  to 
be  tested  is  opposite  to,  and  13  inches  from,  a  round 


PERIPHERAL   VISION. 


white  disc  10  millimeters  in  diameter,  fixed  in  the 
center  of  a  semicircle.  As  the  eye  fixes  the  disc 
the  physician  at  the  back  of  the  perimeter  watches 
the  patient's  eye  that  it  remains  fixed  during  each 
step  of  the  examination.  Then  with  either  of  his 


FIG.  69. — McHardy's  Perimeter. 

hands  the  physician  revolves  the  milled  wheel  at 
the  back  of  the  semicircle  and  thereby  a  carrier  is 
made  to  travel  along  the  inner  side  of  the  semi- 
circle by  means  of  pulley  and  cord.  This  carrier 
contains  a  disc  with  various  colors  upon  it  and  any 
one  of  these  colors  may  be  exposed  to  most  any 
convenient  size  as  the  physician  may  select.  A 
field  chart  or  blank  (Fig.  70)  is  placed  in  the 
bracket  attached  to  the  back  of  the  perimeter. 
There  is  a  small  steel  needle  at  the  back  of  the 
semicircle  near  the  milled  wheel.  The  semicircle 


144 


THE    OPHTHALMOSCOPE. 


will  take  any  meridian  in  which  the  physician 
wished  to  place  it  by  merely  pressing  it  with  his 
hand.  The  inner  surface  of  the  semicircle  should 
always  be  uniformly  illuminated.  The  physician 
usually  places  the  carrier  with  its  selected  color  one 
centimeter  in  size,  at  the  extreme  end  of  the  semi- 


FIG.  70. — Field  charts  for  Right  and  Left  Eye. 

circle  and  gradually  brings  it  toward  the  center  on 
which  the  patient  is  fixing.  As  the  carrier  with 
its  .exposed  color  is  brought  toward  the  center  (by 
the  physician  turning  the  milled  wheel)  the  patient 
is  instructed  to  tell  as  soon  as  the  peripheral  object 
comes  into  view.  When  this  is  mentioned  the  phy- 
sician stops  turning  the  wheel  and  presses  the 
chart  against  the  steel  needle,  which  makes  a  punc- 
ture at  a  point  in  the  chart  corresponding  to  the  de- 
gree mark  on  the  semicircle.  In  this  way  the  various 
meridians  are  recorded  on  the  chart.  Usually  they 


PERIPHERAL   VISION.  145 

are  15  degrees  apart,  though  they  may  be  made  closer 
if  desired.  After  the  meridians  have  been  recorded 
the  physician  connects  the  individual  points  with 
straight  lines,  using  pencil  or  pen,  and  these  con- 
nected points  represent  the  outermost  limit  of 
vision.  The  record  is  made  in  the  same  way  for 
the  various  colors.  That  for  white  is  spoken  of 
as  the  form  field. 

The  peripheral  field  is  naturally  reduced  in  the 
direction  of  the  overhanging  brow  and  in  the  di- 
rection of  the  nose,  and  therefore  it  is  not  so  re- 
stricted downward  and  outward. 

If  a  perimeter  is  not  at  hand  for  recording 
peripheral  vision  the  record  may  be  made  upon  a 
blackboard,  but  it  must  be  remembered  that  the 
record  thus  obtained  upon  a  plane  surface  is  quite 
different  from  the  perimetric  findings.  An  ex- 
cellent method  and  one  always  at  hand  for  making 
an  approximate  test,  is  for  the  physician  to  sit 
facing  the  patient  so  that  their  eyes  are  about  26 
inches  apart.  The  patient  closes  the  eye  not  being 
tested  and  the  physician  closes  his  eye  that  is  di- 
rectly opposite  to  the  one  the  patient  closes,  or  the 
physician  keeps  his  right  eye  open  when  testing  the 
patient's  left  eye,  and  vice  versa.  In  this  position 
with  the  eye  of  the  physician  and  patient  fixing 
each  the  other,  the  physician  uses  the  end  of  a  black 
lead  pencil  or  a  black  pen  holder  as  a  finder,  the  end 
of  the  finder  having  a  small  piece  of  white  paper  a 
quarter  of  an  inch  wide  wrapped  around  it.  The 


146  THE   OPHTHALMOSCOPE. 

physician  moves  this  finder  inward  from  arm's 
length  midway  between  his  and  the  patient's  eye. 
The  physician's  peripheral  vision  being  normal,  he 
will  know  at  once  when  the  patient's  eye  should 
recognize  the  white  paper.  Colored  papers  may  be 
used  in  the  same  way.  The  end  of  the  handle  of 
the  Morton  ophthalmoscope  is  adapted  admirably 
for  this  purpose.  The  field  of  vision  taken  in 
this  way  is  not  exact,  neither  can  it  be  exactly  re- 
corded, but  it  is  often  most  suggestive  and  of  great 
value,  until  a  careful  perimetric  tracing  can  be  made 
later.  The  normal  peripheral  field,  while  of  the 
same  outline  as  the  chart,  is  not  the  same  size  for  all 
colors;  that  for  white  (or  form)  is  the  outermost 
and  largest,  then  comes  blue,  then  red  and  then 
green.  The  field  of  vision  may  also  be  taken  with 
two  lighted  candles  in  a  dark  room.  One  candle  is 
held  in  front  of  the  eye,  and  the  other  candle  is  car- 
ried through  the  various  meridians.  This  is  known 
as  the  candle  field.  This  is  not  exact.  It  is  merely 
suggestive. 

Scotoma  (O-KOTO?,  darkness).  The  one  spot  in 
the  field  of  vision  which  does  not  see  and  is  therefore 
normally  blind,  is  called  the  physiologic  blind  spot, 
or  Mariotte's  blind  spot,  and  is  situated  about  i£_ 
degrees  to  the  outside  of  the  point  of  fixation  (o 
in  Fig.  70),  this  corresponds  to  the  entrance  of  the 
optic  nerve.  Scotomata  are  recognized  when  the 
field  of  vision  contains  areas  or  spaces  which  are 
defective  in  their  normal  seeing  quality  or  con- 


SCOTOMA.  147 

tracted  or  distorted  in  outline  by  certain  diseases  of 
the  eye  itself  and  also  by  various  general  diseases. 

Concentric  contraction  of  the  field  of  vision  is  a 
form  of  scotoma,  in  which  peripheral  vision  is  re- 
duced in  size  in  all  meridians,  depending  upon  the 
stage  of  the  disease  in  which  this  condition  is 
found. 

The  size  of  the  normal  field  is  shown  in  Fig.  70. 
The  field  of  vision  may  be  cut  off  in  quadrants  or 
sectors  or  halves ;  this  latter  is  spoken  of  as  "  hemi- 
anopic  "  or  half  field.  In  making  the  test  for 
scotoma  the  test  object  must  be  quite  small,  2  to  4 
millimeters  in  size. 

Central  Scotoma.  This  indicates  the  loss  of 
good  central  vision,  it  may  be  partial  or  complete, 
and  is  found  in  macular  diseases  from  syphilis, 
myopia,  and  from  toxic  amblyopia,  etc.  Scotomata 
are  also  classed  as  paracentral,  peripheral  and  ring. 

A  scotoma  is  said  to  be  positive  when  the  patient 
is  conscious  of  a  dark  area  in  his  field.  A  scotoma 
is  said  to  be  negative  when  the  patient  has  a  sco- 
toma and  is  not  conscious  of  its  presence.  A  nega- 
tive scotoma  may  be  absolute  or  relative,  the  for- 
mer when  white  and  colors  cannot  be  recognized 
and  the  latter  (relative)  when  the  light  sense  is 
diminished.  Frequent  reference  to  visual  acuity 
and  the  field  of  vision  will  be  made  in  the  considera- 
tion of  ophthalmoscopy. 


CHAPTER   VII. 

RETINAL    VESSELS.     HEMORRHAGES.     PIGMENT     CHANGES. 
HYPEREMIA.    ANEMIA.     EMBOLISM.     THROMBOSIS. 

The  Retinal  Vessels.  Pressure  upon  the  nor- 
mal eyeball  with  the  end  of  the  finger,  while  the 
observer  views  the  retinal  vessels,  will  show  an 
impediment  to  the  blood  current  entering  and  leav- 
ing the  eye  and  with  the  result  that  the  blood  is 
held  in  the  retinal  vessels.  Great  pressure,  if  the 
subject  will  tolerate  it,  shows  an  entire  emptying 
of  the  vessels  on  the  disc.  The  light  streak  in  the 
vessels  is  consistently  diminished  or  absent,  accord- 
ing to  the  amount  of  pressure,  and  the  length  of 
time  the  pressure  is  maintained.  Great  pressure 
may  blanch  the  disc  to  a  distinct  whiteness  from 
its  normal  color.  The  statement  that  the  nor- 
mal proportion  in  size  between  arteries  and  veins 
is  as  two  to  three  is  particularly  true  of  the  vessels 
in  the  retina,  but  it  is  not  true  of  the  vessels  on  the 
disc,  which  may  appear  to  grow  narrow  or  re- 
stricted and  quite  frequently  a  vein  on  the  disc  may 
appear  abnormally  large.  However,  any  great  in- 
crease or  diminution  in  the  size  or  breadth  of  a 
vessel  or  part  of  a  vessel  in  the  eye  ground,  aside 
from  the  disc  is  quite  indicative  of  disease;  for 
instance,  arteries  and  veins  may  both  be  increased 

148 


THE    RETINAL    VESSELS.  149 

in  diameter  or  the  arteries  may  remain  normal  and 
the  veins  diminish,  or,  what  is  much  more  usual, 
the  veins  may  become  greatly  increased  in  width. 
Changes  in  the  retinal  vessels  are  not  always  easily 
detected  unless  the  condition  is  well  marked  or  care- 
fully loc  Jted  for,  simply  because  there  are  normally 
many  differences,  and  it  is  therefore  good  practice 
to  compare  the  size  of  the  vessels  in  the  two  eyes. 
This  careful  comparison  will  at  least  make  a  diag- 
nosis of  a  systemic  condition,  as  compared  with  a 
local  manifestation.  The  fact  must  also  be  borne  in 
mind,  that  there  is  an  occasional  exception  to  this 
comparison  of  relative  size  between  arteries  and 
veins  when  there  happens  to  be  two  veins  accom- 
panying an  artery,  or  two  arteries  accompanying 
a  vein. 

Increase  in  Diameter  of  Veins.  These  are  usu- 
ally seen  in  inflammation  of  the  retina  where  the 
disc  is  also  involved,  and  at  the  same  time  the 
veins  may  become  tortuous,  while  the  arteries  are 
diminished  in  size.  This  increase  in  the  diameter 
of  the  veins  may  be  limited  to  only  a  few  of  the 
veins  or  possibly  the  increase  affects  but  one  vein 
or  a  part  of  a  vein,  and  is  due  to  an  inflammation 
involving  the  vessel  walls  or  to  pressure  on  the 
venous  trunk  in  the  membrana  cribrosa,  or  after 
it  leaves  the  eye,  or  it  may  be  due  to  some  general 
venous  congestion.  Veins  increased  in  diameter 
(beyond  the  normal  size)  are  seen  in  specific  and 
splenic  retinitis,  and  in  fact  in  nearly  all  varie- 


I5O  THE   OPHTHALMOSCOPE. 

ties  of  retinitis;  the  early  stages  of  fever,  such  as 
typhoid;  also  in  pleurisy,  pneumonia,  asthma,  and 
in  congestion  and  inflammation  of  the  brain  or  its 
meninges;  in  various  forms  of  heart  disease  and 
anemia.  Any  impediment  to  the  return  blood 
stream  from  the  eye  will  naturally  cause  the  veins 
to  become  distended,  and  this  is  seen  to  be  the  case 
in  such  diseases  of  the  eye  as  glaucoma  and  oplis 
nejjritis,  and  undue  pressure  on  the  venous  trunk 
between  the  eye  and  the  heart,  as  in  diseases  of 
the  orbit,  erysipelas,  cellulitis,  growths,  etc.;  and 
pressure  in  the  neck  from  goitre  and  various 
growths ;  and  in  various  diseases  of  the  lungs,  espe- 
cially phthisis. 

Decrease  in  Diameter  of  the  Veins.  This  con- 
dition of  the  veins  is  not  at  all  common,  and  when 
seen  is  usually  a  condition  or  disease  of  the  eye 
itself,  such  as  atrophy  of  the  retina  or  optic  nerve. 
In  embolism  of  the  central  artery  the  veins  in  some 
portions  are  quite  narrow.  The  diameter  of  the 
vein  decreases  in  degeneration  of  the  vessel  itself. 

Increase  in  Diameter  of  the  Arteries.  This 
condition,  like  diminution  in  the  size  of  the  veins, 
is  very  rare  indeed,  and  when  recognized  is  usu- 
ally caused  by  some  disease  of  the  coats  of  the 
artery  which  has  weakened  its  contractile  power, 
and  yet  this  condition  may  be  seen  when  the  heart 
action  is  increased;  also  in  early  stages  of  fever, 
pneumonia,  pleurisy,  brain  disease  and  leukemic 
retinitis. 


DIAMETER    OF    ARTERIES. 

Decrease   in   the   Diameter   of   the   Arteries. 

This  condition  of  the  arteries  is  much  more  com- 
mon than  an  increase  in  their  size.  Intra-ocular 
pressure  which  keeps  the  blood  from  entering  the 
eye  as  freely  as  it  otherwise  would,  will  cause  a 
diminution  in  the  size  of  the  arteries;  therefore,  a 
decrease  in  the  diameter  of  the  arteries  is  seen  in 
glaucoma,  embolism,  papillitis,  thrombosis,  hemor- 
rhagic  retinitis,  etc.  Optic  and  retinal  atrophy  fol- 
lowing inflammation  leaves  the  arteries  not  only  di- 
minished in  calibre  but  also  with  a  white  line  seen 
in  the  vessel  for  a  considerable  distance  from  the 
disc;  this  is  due  to  sclerosis  of  the  middle  coat  of 
the  artery  and  this  whitening  of  the  coat  may  be 
sufficiently  dense  to  obscure  any  view  of  the  blood 
stream,  the  artery  or  arteries  looking  like  white 
threads  or  cords.  The  arteries  are  seen  to  be  di- 
minished in  size  in  conditions  resulting  from  weak 
heart,  also  anemia  and  chlorosis,  epilepsy,  etc.  Reti- 
nitis pigmentosa  causes  a  diminution  in  size  of 
both  arteries  and  veins.  A  thickening  in  the 
arterial  coats  and  a  diminution  in  the  calibre  of 
the  arteries  results  in  albuminunc_retinitis. 

Changes  in  Vessel  Walls — Arteriosclerosis. 
These  may  be  designated  as  fatty  degeneration, 
chalky  deposits,  perivasculitis  and  sclerosis;  the 
arteries  are  unevenly  narrowed  or  the  arteries  may 
be  bordered  by  extravasations,  and  the  veins  may 
be  distended,  showing  many  narrowings  or  con- 
strictions like  the  arteries.  These  conditions  are 


152  THE    OPHTHALMOSCOPE. 

usually  recognized  with  the  ophthalmoscope  by 
diminution  in  the  normal  transparency  of  the  ves- 
sel walls.  The  vessel  walls  having  their  lumen  di- 
minished will  naturally  reveal  this  condition,  when- 
ever there  is  any  crossing  over  of  the  vessels  as  the 
blood  current  is  diminished  at  this  crossing,  if  there 
is  any  pressure  exerted,  and  then  the  vessel  again 
refills  after  the  crossing  (Plates  VI.  and  X.).  One 
vessel  or  a  part  of  a  vessel,  or  all  the  vessels,  may 
be  affected  by  these  changes.  Sclerosis  of  the 
vessels  is  quite  conspicuous  in  retinitis  pig- 
mentosa,  whether  of  the  congenital  or  acquired 
(specific)  variety.  Sclerosis  of  the  vessels  may  be 
seen  in  any  form  of  retinitis,  but  especially  in  the 
nephritic  variety. 

Perivasculitis.  This  is  an  increase  or  a  hyper- 
plasia  of  the  connective  tissue  about  the  vessels, 
principally  and  usually  the  arteries  (periarteritis) 
(Plate  IV.).  The  condition  is  recognized  with 
the  ophthalmoscope  by  the  yellowish-white  color  of 
the  vessels,  which  appear  in  some  instances,  when 
inflammation  and  proliferation  is  excessive,  to  look 
like  white  threads.  If  the  inflammation  is  not  so 
severe  the  sides  of  the  vessels  appear  to  have  a 
yellowish-white  color,  or  the  vessels  appear  to  be 
bordered  with  delicate  or  narrow  white  lines,  seen 
in  eyes  having  post-papillitic  atrophy  or  atrophy  of 
the  retina. 

Vessels  of  New  Formation  in  the  Retina. 
These  are  very  rare  indeed  and  when  present  are 


RETINITIS    PROLIFERANS.  153 

seen  to  run  in  the  same  direction  usually  as  the 
large  vessels;  they  appear  in  isolated  areas  and  a 
common  position  is  on,  or  near,  the  disc.  They 
maintain  about  the  same  caliber  throughout,  with 
very  little,  if  any,  diminution  in  size,  and  are  often 
quite  tortuous,  and  on  this  account  have  been  de- 
scribed as  "  cork  screw."  Growths  in  the  choroid 
and  retina  may  show  vessels  of  new  formation. 

Vessels  of  New  Formation  in  the  Vitreous 
(Retinitis  Prolif erans) .  Like  vessels  of  new  for- 
mation in  the  retina,  these  form  a  very  rare  condi- 
tion, and  from  the  same  cause  presumably,  viz., 
some  severe  inflammation  of  the  retina  in  which 
the  connective  tissue  about  the  retinal  vessels,  or 
a  single  retinal  vessel,  has  become  vascularized. 
During  this  severe  inflammation  of  the  retina  no 
distinct  view  of  the  eye  ground  can  be  made  out, 
but  when  this  inflammation  subsides  these  newly 
formed  vessels,  supported  by  connective  tissue, 
may  be  recognized  extending  across  the  fundus 
and  into  the  vitreous,  resembling  bands  with  many 
fine  loops  of  vessels  of  varying  length,  and  occa- 
sionally these  vessels  appear  like  strands  of  rav- 
elled thread.  Vessels  of  new  formation  are  ap- 
parently venous. 

Aneurisms,  or  Varicosities,  or  Dilatations  of 
the  Retinal  Vessels.  These  are  rare  conditions, 
and  may  be  congenital  or  caused  by  trauma  or  in- 
flammation. A  dilation  of  a  retinal  vein  on  the  disc 
is  not  uncommon  but  has  erroneously  been  spoken 


154  THE   OPHTHALMOSCOPE. 

of  as  an  aneurism.  An  aneurism  of  a  retinal  artery 
would  be  recognized  by  its  more  or  less  rounded 
shape  in  the  course  of  the  artery,  resembling  a  bead 
on  a  string  or  thread,  the  light  streak  in  the  vessel 
being  interrupted  at  the  aneurism. 

Arterial  Pulsation.  This  is  not  a  common  con- 
dition, and  when  present  is  usually  pathologic;  if 
seen  extending  well  into  the  retina  beyond  the 
disc  it  usually  signifies  aortic  valvular  disease  (in- 
sufficiency). Pulsation  of  the  arteries  on  the  disc 
is  most  commonly  seen  in  glaucoma,  a  point  in  diag- 
nosis in  this  disease. 

Owing  to  the  position  of  the  retinal  vessels  be- 
tween, the  choroid  and  the  vitreous,  they  naturally 
receive  pressure  from  the  front,  and  the  back,  and 
on  this  account  they  are  found  to  be  oval  on  sec- 
tion, the  horizontal  diameter  being  greater  than 
the  perpendicular.  If  the  retinal  vessels  are  dis- 
tended they  naturally  approximate  a  circular 
shape;  hence  the  broader  the  light  streak,  the  flat- 
ter the  vessel,  and  vice  versa. 

Venous  Pulsation.  This  is  not  necessarily  path- 
ologic; on  the  contrary,  it  is  normal  in  most  cases 
when  seen  upon  the  disc  or  extending  a  short  dis- 
tance into  the  retina  (see  Chapter  IV.).  It  may 
be  seen  with  an  increase  of  intra-ocular  tension. 

Hemorrhages.  There  is  no  portion  of  the 
retina  which  may  be  considered  exempt  from  the 
presence  of  hemorrhages,  and  these  may  occur 
in  any  layer  or  in  any  portion  of  its  surface.  Hem- 


HEMORRHAGES.  156 

orrhages  from  the  retinal  vessels  vary  in  their 
color,  shape,  size  and  location.  Most  hemorrhages 
at  the  time  of  their  occurrence  are  darker  than  the 
general  f  undus  reflex,  being  bright  red,  and  later  be- 
come darker  in  color,  and  may  disappear  by  absorp- 
tion of  the  clot,  and  no  evidence  of  their  previous 
existence  will  be  recognized;  yet  occasionally  some 
pigment  may  appear  after  the  hemorrhage  has  been 
absorbed,  but  this  is  rare.  A  very  profuse  hemor- 
rhage may  leave  its  mark  by  the  presence  of 
spots  of  a  brownish  or  brownish-black  color.  As 
a  rupture  of  a  retinal  vessel  only  takes  place  by 
violence,  hemorrhages  in  the  retina  from  disease 
must  take  place  by  the  escape  of  blood  through 
the  vessel  walls.  A  very  natural  inference  in  re- 
gard to  hemorrhages  in  the  retina,  as  elsewhere, 
would  be  that  they  would  occur  in  the  periphery  of 
the  eye  ground  where  the  vessels  are  small  and  pre- 
sumably weaker,  but  while  this  is  undoubtedly  good 
reasoning,  yet  the  very  reverse  is  the  case;  the 
hemorrhages  occurring  from  the  large  vessels 
whose  walls  cannot  resist  the  pressure,  which  pres- 
sure is  very  likely  much  greater  in  the  large  ves- 
sels than  in  the  small  ones;  in  other  words,  the 
walls  of  the  smaller  vessels  must  be  stronger  or  the 
pressure  is  less  by  the  time  the  blood  stream  gets 
to  them,  or  both  conditions  may  exist.  With  this 
understanding  of  the  vessels  affected,  it  will  be  bet- 
ter appreciated  why  the  most  common  seat  of  reti- 
nal hemorrhages  is  at  the  disc  and  its  immediate 


15'->  THE   OPHTHALMOSCOPE. 

neighborhood.  The  next  most  common  situation 
for  the  presence  of  retinal  hemorrhages  is  at  the 
macular  region,  and  naturally  hemorrhages  at  the 
macula  obscure  vision  more  and  more  as  the  fovea 
centralis  is  encroached  upon.  Hemorrhages  in  the 
periphery  are  of  capillary  origin  and  have  this  sig- 
nificance, that  the  morbid  process  is  either  in  the 
capillary  vessel  walls,  or  if  in  the  large  vessels  also 
it  is  the  small  vessels  which  are  mostly  affected, 
and  usually  this  means  a  grave  general  disease  and 
is  much  more  significant,  if  the  hemorrhages  are 
in  the  deep  layers  of  the  retina. 

Shape,  Size  and  Location.  Hemorrhages  in 
the  nerve  fiber  layer  (inner  layers)  of  the  retina, 
appear  more  or  less  streaked,  having  rather 
straight  edges  or  sides,  and  their  ends,  especially 
the  distal  ends,  resemble  the  edge  of  a  feather  or 
gas  flame,  and  are  therefore  commonly  described 
as  "  feathered  edged  "  or  "  flame-shaped."  The 
cause  of  this  peculiar  striation  is  that  the  blood 
works  its  way  between  the  nerve  fibers,  which  ap- 
pear to  cut  it  into  fine  lines  (Plates  V.  and  VI.). 
Hemorrhages  in  the  deep  layers  (outer  layers)  of 
the  retina  are  not  so  characteristically  marked  but 
appear  as  small  red  dots,  round  or  irregularly 
shaped  (Plate  VI.).  Hemorrhages  between  the 
retina  and  the  choroid  may  appear  round  or  oval 
with  sharp  cut  edges;  the  retinal  vessels  may  be 
seen  passing  over  such  hemorrhages,  which  would 
indicate  at  once  that  the  hemorrhage  must  be  back 


HEMORRHAGES.  1 5  7 

of  the  retina,  and  of  course  the  retina  must  be  more 
or  less  elevated  at  the  location  of  the  hemorrhage. 
A  hemorrhage  between  the  retina  and  the  vitreous 
called  a  subhyaloid  hemorrhage,  has  a  circular 
shape  and  sharp  edges,  and  naturally  such  a  hem- 
orrhage obscures  any  view  of  the  retinal  vessel  be- 
hind it.  A  subhyaloid  hemorrhage  may  have  its 
upper  edge  quite  straight  and  its  lower  edge  a  con- 
vexity downward ;  this  is  due  to  the  blood  settling  by 
gravity.  Retinal  hemorrhages  may  appear  isolated 
without  any  apparent  connection  with  vessels,  but 
usually  they  lie  near  the  vessels.  A  retinal  hemor- 
rhage may  be  so  large  that  it  will  break  through 
the  hyaloid  membrane  and  escape  into  the  vitreous, 
and  in  this  way  it  is  a  frequent  cause  of  vitreous 
opacities. 

Causes  of  Retinal  Hemorrhages.  Retinal 
hemorrhages  may  be  caused  by  over-distension  of 
the  vessel,  or  degeneration  of  the  vessel  wall,  by 
alteration  of  the  blood  itself,  and  occasionally  by 
injury;  all  inflammatory  diseases  of  the  retina 
itself;  increased  heart  action;  abnormal  and  sud- 
den suppression  of  the  menses;  diseases  of  the 
brain,  kidneys  and  spleen;  diabetes;  pernicious 
anemia,  leukemia;  gout;  tuberculosis;  scrofula; 
purpura;  hemorrhagic  diathesis;  degeneration  of 
vessel  walls;  thrombosis  and  embolism;  injuries; 
etc. 

Changes  in  the  Vascularity  of  the  Retina. 
These  may  be  many  or  few;  they  may  be  limited 


158  THE   OPHTHALMOSCOPE. 

to  several  vessels  or  to  a  single  vessel,  or  a  part 
of  a  vessel.  As  an  extreme  condition  of  pallor  or 
diminution  of  the  blood  supply  to  the  retina,  may 
be  mentioned  embolism  of  the  central  artery  (Plate 
II.);  and  as  the  extreme  condition  of  engorge- 
ment of  the  retina  may  be  mentioned  thrombosis 
of  the  central  vein  (Plate  III.). 

Pigment  Changes.  Normal  pigmentation  more 
or  less  extensive  may  be  seen  at  the  choroidal  ring 
in  almost  every  eye  (Plate  I.)  and  occasionally  an 
innocent  amount  of  pigment  may  be  seen  in  a  small 
mass  at  the  upper  edge  of  the  disc,  and  not  infre- 
quently a  small  round  spot  of  pigment  the  size  of 
a  pin  head,  or  a  trifle  larger,  may  be  seen  at  some 
distant  point  in  the  retina  where  it  is  not  of  any 
serious  consequence  (Plate  VIII.),  and  yet  each 
spot  of  pigment,  wherever  situated,  should  have 
careful  consideration.  Scattered  areas  of  pig- 
mentation should  always  be  looked  upon  with  sus- 
picion, especially  those  connected  with  changes  in 
the  choroidal  coat  (Plate  XL)  and  those  seen  upon 
the  retinal  vessels. 

Hyperemia  of  the  Retina.  It  is  not  an  easy 
matter  for  the  beginner  in  ophthalmoscopy,  to  ap- 
preciate this  characteristic  condition  of  the  eye 
ground,  and  yet  it  is  a  most  important  one,  and  one 
often  overlooked,  if  the  observer  is  not  extremely 
cautious.  Overlooked  in  the  sense  that  it  may  be 
so  well  marked  as  to  suggest  a  beginning  retinitis 
or  papillitis;  however,  the  patient's  history,  etc., 


IIYPEREMIA    OF    RETINA.  159 

will  surely  put  the  observer  on  his  guard.    Hyper- 
emia  of  the  retina  is  manifest  principally  upon  the 
disc  and  its  immediate  neighborhood  by  a  conges- 
tion of  the  retinal  capillary  vessels  which  lie  in  the 
most  anterior  layers  of  the  retina,  and  as  these 
vessels  are  not  ordinarily  prominent   in  healthy 
eyes,  their  congestion  will  give  the  retina  a  striped 
appearance  about  the  nerve,  and  its  edges  will  be- 
come somewhat  obscure  or  "  wgolly."  The  nerve 
(intermediate  zone)   may  have  a  red  brick  dust 
color.    The  macular  region,  if  carefully  observed, 
will  appear  of  a  much  darker  hue  than  is  consistent 
or  in  keeping  with  the  general  appearance  of  an 
otherwise   quiet   eye.     This    hyperemia   of   the 
retina,  described  by  Jaeger  as  "  irritation  of  the 
retina."  is  the  unique  picture  often  seen  in  eyes 
with  refractive  errors,  especially  of  the  hyperopic 
(hypermetropic)  variety.     As  nearly  80  per  cent. 
of  all  eyes  have  some  form  of  hyperopia,  then, 
as  just  stated,  "  irritation  of  the  retina  "  is  not  such 
an  uncommon  condition,  especially  if  the  eyes  have 
not  been  "  glassed,"  or  if  the  glasses  are  not  correct. 
Retinal  irritation  as  just  described  is  brought 
/about  therefore  by  accommodative  effort  and  the 
1  condition  is  recognized  as  a  disease  and  called  ac- 
\commodative  asthenopia.     The  symptoms  are  in 
keeping  with  the  irritated  and  fatigued  retina  and 
ciliary  muscle,  though  the  vision  is  not  as  much  at 
variance  as  might  be  expected  by  the  refractive  er- 
ror present;  the  patient,  however,  complains  of  his 


l6O  THE   OPHTHALMOSCOPE. 

eyes  feeling  tired,  the  eyeballs  ache,  blurred  vision 
comes  on  after  prolonged  near  work,  or  after  a  time 
this  blurred  vision  may  come  on  promptly  after  using 
the  eyes  for  only  a  few  minutes,  while  looking  atten- 
tively at  any  nearby  object.  With  the  blurred  vision 
there  is  often  a  dread  of  light  (photophobia). 
Frontal  headache  (brow  ache)  over  both  eyes  or 
over  one  more  than  its  fellow,  usually  over  the  eye 
with  the  least  refractive  error.  The  frontal  head- 
ache may  extend  into  the  temples,  a  temporal  head- 
ache, and  nausea  and  dizziness  may  also  be  present. 
If  the  patient  forcibly  concentrates  his  vision,  the 
object  looked  at  may  soon  appear  unsteady  or  in- 
distinct, and  then  the  eyes  may  become  suffused  with 
the  lacrimal  fluid.  The  treatment  is  rest  with  a 
cycloplegic  and  dark  glasses,  and  carefully  selected 
glasses,  the  eyes  being  made  equal  to  the  emmetropic 
or  standard  condition,  which  is  a  minimum  amount 
of  accommodative  effort  for  the  work  at  which  the 
eyes  are  engaged. 

RETINAL  IRRITATION,  OR  HYPEREMIA,  FROM  EXPOSURE 
OF  THE  EYES  TO  SUNLIGHT  (SOLAR  RETINITIS);  TO 
ELECTRIC  LIGHT  AND  FLASHES  OF  ELECTRIC  LIGHT 
(ELECTRIC  RETINITIS);  TO  REFLECTION  FROM  THE 
SNOW  (SNOW  BLINDNESS). 

The  symptoms  of  these  conditions  are,  photo- 
phobia and  lacrimation  with  irritation  of  the  con- 
junctiva. The  patient's  history  gives  the  cause. 
Sun  blindness  and  snow  blindness  usually  re- 
cover after  the  use  of  dark  glasses  for  a  few  days 
unless  the  condition  is  complicated  by  conjunc- 


ANEMIA   OF   RETINA.  l6l 

tivitis  and  ulcer  of  the  cornea  or  macular  changes, 
when  appropriate  treatment  for  these  compli- 
cations must  be  met.  Electric  retinitis  is  a  much 
more  serious  matter,  for  when  the  exposure  has 
been  a  lengthy  one,  or  the  electric  flash  has 
been  intense,  there  may  be  extensive  changes 
set  up  in  the  macula  and  macular  region  of  a  low 
grade  retino-choroiditis,  which  may  leave  per- 
manent changes  and  damage  to  central  vision.  The 
treatment  for  such  cases  is  rest  of  the  eyes  with 
dark  glasses  and  restraint  from  any  use  of  the  eyes 
whatever  until  fully  recovered.  It  may  be  neces- 
sary to  institute  internal  medication,  and  to  use  a 
solution  of  atropin  in  the  eyes  for  a  few  days.  If 
snow  blindness  is  complicated  with  changes  in  the 
macula,  then  a  similar  line  of  treatment  must  be 
carried  out. 

Anemia  of  the  Retina.  This  is  the  reverse  of 
hyperemia  and  therefore  gives  something  of  a  re- 
verse picture,  and  the  striations  at  the  disc  edges  are 
absent.  The  disc  is  pale  and  the  general  fundus  re- 
flex is  lighter  in  color  than  normal.  The  arteries 
are  not  distended,  and  if  compression  or  embolism 
of  the  central  artery  is  present,  the  picture  of 
anemia  of  the  retina  is  typical  (Plate  II.).  The 
ophthalmoscope  reveals  diminished  amount  of  blood 
in  retinal  vessels  by  the  absence  of  the  light  streak, 
which,  if  present  at  all  is  very  narrow  and  does  not 
extend  far  into  the  eye  ground.  The  veins  and 
arteries  are  equally  affected.  There  are  exceptions 


1 62  THE   OPHTHALMOSCOPE. 

to  this  broad  statement  and  the  arteries  may  be 
small  and  veins  large.  Naturally  the  eye  ground  in 
anemia  appears  paler  than  normal  and  the  pale 
condition  is  in  keeping  with  the  light  color  of  the 
disc,  so  that  the  line  of  demarkation  between  disc 
and  surrounding  eye  ground,  is  not  always  very 
well  marked.  This  condition  must  not  be  con- 
founded with  optic  atrophy  where  the  contrast  is 
very  marked,  but  in  the  beginning  of  optic  atrophy 
the  contrast  is  not  so  conspicuous.  Systemic 
anemia  from  any  cause  will  often  express  itself  in 
anemia  of  the  retina,  but  a  pale  face  does  not  neces- 
sarily mean  anemia  of  the  retina,  nor  does  a  florid 
complexion  necessarily  mean  hyperemia  of  the 
retina.  While  admitting  that  a  patient's  color  may 
be  an  index  of  his  blood  condition,  yet  a  pale  com- 
plexion may  be  due  to  a  want  of  blood  in  the  capil- 
laries of  the  skin  and  no  change  be  noted  in  the 
retina,  and  a  florid  complexion  may  mean  blood  in 
the  capillaries  of  the  face,  and  yet  the  system  be 
anemic,  as  indicated  by  the  retina. 

Differential  Diagnosis,  as  Revealed  with  the 
Ophthalmoscope  between  Pallor  of  the  Disc  and 
Retina  in  Anemia  and  that  Caused  by  Optic 
Atrophy. 

Anemia.  Atrophy  (Plate  X.). 

Pallor  of  disc.  White  disc. 

Surrounding    eye    ground  also       Surrounding  eye  ground  appears 
pale.  redder  than  normal. 


PLATE  II. 

EMBOLISM  OF  THE  CENTRAL  ARTERY  OF  THE  LEFT  EYE.    DIRECT 
METHOD. 

S.  B.     Male.    Aged  61  years. 

History.  Embolism  came  without  any  warning  in  a  man  other- 
wise apparently  well.  (Two  years  later,  without  apparent  cause,  a 
large  hemorrhage  took  place  in  this  same  eye,  followed  by  iritis,  a 
dislocation  of  the  lens  into  the  vitreous  and  the  development  of 
absolute  glaucoma  requiring  enucleation.)  Large,  oval-shaped, 
blanched  area,  which  includes  the  disc  and  macula.  Cherry-red  spot 
at  the  macula.  Intermediate  zone  of  the  disc  shows  apparently 
normal  except  for  a  faint  fogginess.  The  arteries  are  almost  empty 
and  the  smaller  ones  have  the  blood  stream  broken  in  different 
places.  The  arteries  have  lost  their  light  streak.  The  veins  are 
slightly  distended,  but  not  tortuous;  the  light  streak  is  almost  lost 
in  the  veins,  but  can  be  faintly  seen. 


164 


PLATE    II 


Embolism  of  the  Central  Rrtzrij 


PERNICIOUS   ANEMIA.  1 67 

Anemia.  Atrophy  (Plate  X.). 

Relative    size    of    arteries    and      Arteries    smaller    and    in    late 

veins  remains  about  the  same,          stage  of  atrophy  are  reduced 

vessels  may  not  be  uniformly          in    number.     In    early    stage 

filled.  veins  are  larger.    In  late  stage 

veins  are  diminished,  and  not 
readily  distinguished  from  ar- 
teries. 

Disc  surface  not  sunken.  Disc    surface    in    late    stage    is 

sunken,  becoming  concave  or 
saucer  shaped. 

Pallor  due  to  want  of  blood  and  Pallor  due  to  shrunken  capil- 
hence  capillaries  in  the  disc  do  laries  in  disc  and  also  increase 
not  appear.  of  connective  tissue. 

Causes  of  Anemia.  Fainting  and  loss  of  blood 
and  general  anemia  will  cause  pallor  of  the  retina 
and  disc.  Pallor  of  the  retina  and  disc  is  also  seen 
in  true  migraine  and  may  also  be  caused  temporarily 
by  toxic  doses  of  quinine  and  salicylic  acid. 

Treatment.  Iron  and  arsenic,  etc.,  for  the  gen- 
eral anemia;  appropriate  treatment  for  the  weak 
heart. 

Pernicious  Anemia.  The  retina  in  pernicious 
anemia  is  not  actively  inflamed.  The  disc  appears 
pale  and  the  edges  woolly,  so  that  the  retina  and 
disc  are  not  separated  by  any  sharp  line.  The  eye 
ground  appears  of  a  yellowish  cast.  Small  hemor- 
rhages appear  in  the  nerve  fiber  layer  and  are  there- 
fore flame-shaped.  Hemorrhages  in  pernicious 
anemia  are  not  a  constant  condition.  This  condi- 
tion of  the  retina  is  also  seen  in  hemophilia,  purpura, 
malaria,  scurvy  (scorbutic  anemia),  etc. 

Embolism  or  Thrombosis  of  Central  Artery  of 
the  Retina  (Plate  II.).  When  there  is  complete 


1 68  THE   OPHTHALMOSCOPE. 

occlusion  of  the  central  artery  of  the  retina  (if 
seen  shortly  after  the  plugging  has  taken  place) 
then  the  following  changes  will  be  observed: 

1.  Change  in  Arteries.    The  large  vessels  are  re- 
duced to  white  lines,  appearing  like  white  threads, 
and  the  small  arteries  cannot  be  seen.     Here  and 
there  in  an  artery  may  be  seen  some  portion  of 
the  blood  stream  broken  into  sections. 

2.  Changes  in  Veins.    These  may  be  normal  but 
usually  they  are  contracted  and  show  irregularities. 

3.  Changes  in  Disc.    The  disc  appears  pale  as  the 
capillaries  are  not  distended. 

4.  Changes  in  Retina.     The  central  portion  of 
this  structure  is  swollen  or  edematous  and  grayish- 
white  in  color,  embracing  the  macula  and  disc,  giv- 
ing the  appearance  of  a  large  horizontally  oval  area 
of  edema.    The  peripheral  portion  of  the  retina  is 
not  similarly  involved.     Many  small  hemorrhages 
may  be  present.    A  cherry  red  spot  occupies  the 
fovea,   resembling  a   round  hemorrhage.     This 
cherry  red  spot  is  caused  by  the  red  of  the  cho- 
roid  appearing  through  the  retina  at  the  macula. 

Embolism  affecting  a  branch  of  the  central 
artery  gives  a  picture  of  changes  consistent  with 
the  retina  correspondingly  affected,  but  the 
cherry  red  spot  may  not  be  present.  The  dilated 
vessel  up  to  the  point  of  plugging  may  be  distinctly 
seen  and  the  remainder  of  the  vessel  lie  empty,  look- 
ing like  a  white  thread  or  containing  sections  of  the 
blood  stream.  Several  weeks  after  the  embolus 


EMBOLISM    OF   RETINA.  169 

has  plugged  the  artery,  the  swelling  of  the  retina 
gradually  disappears  and  with  the  disc  undergoes 
atrophy.  The  vessels  of  the  retina  diminish  until 
they  appear  like  white  threads.  Cholesterin  crys- 
tals and  pigmentation  may  make  their  appearance 
principally  about  the  disc  and  macula.  As  soon  as 
plugging  of  the  central  artery  takes  place,  central 
vision  is  promptly  lost.  If  the  eye  happens  to  be 
supplied  with  a  cilio-retinal  vessel  (see  Chapter  IV. 
and  Plate  I. )  then  some  central  vision  may  be  main- 
tained, otherwise  central  vision  would  be  cut  off. 
Embolism  of  a  branch  of  the  artery  will  cut  off  the 
vision  in  the  field  corresponding  to  that  portion  of 
the  retina  supplied  by  this  branch,  and  vision  may 
remain  quite  good  or  normal  at  the  macula. 

Cause.  This  cannot  be  definitely  determined. 
The  most  common  cause  is  some  disease  in  or  about 
the  heart.  Valvular  disease,  vegetations,  endocar- 
ditis, aneurism  of  the  aorta  and  carotid,  changes  in 
the  vessel  walls  (endarteritis  and  sclerosis),  syph- 
ilis, nephritis,  pregnancy,  etc.  Usually  one  eye 
alone  is  affected. 

Diagnosis.  Sudden  stoppage  of  the  blood 
stream  in  the  arteries,  edema  (opacity)  in  the 
retina,  cherry  red  spot  in  macula. 

Sudden  loss  of  vision,  and  without  pain,  although 
there  may  have  been  some  few  premonitions,  such 
as  slight  dizziness,  slight  headache,  and  possibly 
flashes  of  light.  These  same  symptoms  sometimes 
precede  detachment  of  the  retina. 


170  THE  OPHTHALMOSCOPE. 

Prognosis.  While  this  is  most  unfavorable,  as 
atrophy  usually  follows  and  blindness  is  the  final 
outcome,  yet  the  presence  of  a  cilio-retinal  vessel 
leaves  some  hope  for  what  would  otherwise  be  con- 
sidered an  almost  hopeless  condition. 

Treatment.  With  an  unfavorable  prognosis, 
treatment  seems  almost  a  waste  of  time  and  energy. 
Yet  treatment  must  not  be  withheld,"  as  some  good 
may  be  accomplished  and  has  been  accomplished  in 
a  few  instances.  If  a  history  of  syphilis  is  ob- 
tained or  suspected  the  case  should  be  treated  vigor- 
ously along  these  lines,  viz.,  mercurial  inunctions, 
pilocarpin  sweats,  and  internally  the  iodid  of  pot- 
ash should  be  pushed  to  the  extreme  point  of  toler- 
ance. In  fact,  the  iodid  is  indicated  in  nearly  every 
instance.  The  patient's  heart  should  have  careful 
consideration  and  treatment  if  necessary.  Digital 
massage  to  the  eye  and  nitrate  of  amyl  and  digitalis 
internally  are  recommended. 

Thrombosis  of  the  Central  Vein  (Plate  III.). 
When  this  condition  is  complete  the  following 
changes  will  be  observed : 

1.  Changes  in  the  Disc.     The  disc  appears  ele- 
vated, hazy,  or  opaque  and  its  margins  indistinct 
and  striated,  and  late  in  the  disease,  may  be  hidden 
from  view. 

2.  Changes  in  Retina.    The  entire  eye  ground  is 
covered  with  many  large  hemorrhages,  some  pink 
in  color  but  most  of  them  very  dark  red  with  flame- 
shaped  edges.     The  retina  itself  is  foggy  and 


PLATE  III. 

THROMBOSIS  OF  THE  CENTRAL  VEIN  OF  THE  LEFT  EYE.    ALSO  CALLED 
APOPLEXY  OF  THE  RETINA  AND  HEMORRHAGIC  RETINITIS. 

Mr.  A.  G.  B.    Aged  65  years. 

History.  Good  health  until  two  years  before  coming  under  obser- 
vation. At  that  time  developed  a  swelling  in  right  side  of  the  neck 
which  was  removed  at  Presbyterian  Hospital  in  Philadelphia  and 
microscopically  diagnosed  as  epithelioma.  A  second  operation  at 
the  same  hospital  six  months  later  for  the  same  condition ;  the 
wound  never  healed  and  patient  refused  further  surgical  interfer- 
ence. First  noticed  failing  vision  and  everything  appearing  of  a 
red  color  five  days  before  coming  under  observation. 

Vision  of  right  eye  20/20.     Vision  of  left  eye  1/120. 

Fundus  Changes.  Fundus  of  right  eye  almost  normal  except  for 
one  or  two  small  flame-shaped  hemorrhages  in  neighborhood  of  the 
macula. 

Left  Eye.  Acute  papillitis.  Disc  very  much  swollen  and  apex 
seen  with  +  4  D.  and  fundus  without  any  lens  at  the  sight  hole. 
Arteries  small  and  very  few  of  them  in  view.  The  veins  are  very 
tortuous,  looking  like  half  hoops  or  serpentine,  hence  the  condition 
as  described  in  the  text  of  "  Medusa  Nerve."  The  light  streak  in 
the  veins  is  conspicuous  at  the  top  of  each  loop.  The  hemorrhages 
are  of  all  sizes  and  shapes  and  shades  of  red. 


172 


PLATE    III 


Thrombosis  of  the  Central  Vein 
(So- called  Hemorrhagic  Retinitis) 


THROMBOSIS   OF    CENTRAL   VEIN.  175 

sooner  or  later  becomes  of  a  yellowish-gray  color. 

3.  Changes  in  Veins.     The  veins  are  full  and 
tortuous  and  have  a  blackish  appearance  and  pulsa- 
tion may  be  detected.    The  appearance  of  the  veins 
has  been  compared  to  the  hair  of  Medusa. 

4.  Changes  in  Arteries.     These  are  small  ana 
may  be  hidden  or  invisible.     The  vitreous  usually 
contains  opacities. 

If  thrombosis  affects  a  branch  of  the  vein,  then 
the  above  conditions  would  be  in  keeping  for  the 
corresponding  portion  of  the  retina. 

Cause.  Thrombosis  usually  occurs  in  elderly 
people  who  suffer  with  atheroma  or  heart  disease. 
Phlegmons,  abscesses,  erysipelas  and  inflammatory 
diseases  of  the  orbit  are  a  few  of  the  causes  of 
venous  thrombosis  in  the  retina.  Both  eyes  may  be 
affected,  especially  if  erysipelas  is  the  cause,  though 
usually  one  eye  alone  is  affected.  Prognosis  is  most 
unfavorable,  as  blindness  usually  follows  and  pos- 
sibly enucleation  may  be  necessary  (see  Apoplexy 
of  the  Retina). 

Treatment.  This  is  of  very  little  avail  and  must 
be  directed  to  the  underlying  cause. 


16 


CHAPTER    VIII. 

DISEASES  OF  THE  RETINA. 

Diseases  of  the  Retina.  These  are  many  and 
are  named  principally  from  the  underlying  cause, 
but  no  matter  what  the  cause  may  be,  the  ophthal- 
moscope reveals  one  or  more  of  the  many  changes 
described  on  the  following  pages. 

Inflammation  of  the  Retina  Without  Regard 
to  its  Variety.  For  very  good  reasons  inflamma- 
tion of  the  retina  may  be  divided  into  two  kinds, 
superficial  and  deep,  or  inflammation  of  the  inner 
layers  and  inflammation  of  the  outer  or  deeper 
layers.  When  the  inflammation  affects  the  inner 
layers  the  ophthalmoscopic  picture  is  most  conspic- 
uous, and  yet  with  all  the  conspicuous  disturb- 
ance in  the  retina  central  vision  may  not,  for  the  time 
being,  be  seriously  damaged,  whereas,  when  inflam- 
mation affects  the  deeper  layers  there  may  not  be 
such  apparent  or  prominent  changes,  and  yet  the 
vision  may  be  very  much  diminished.  It  is  hardly 
necessary  to  state  that  it  is  not  always  possible  to 
have  an  inflammation  limited  to  the  inner  or  deeper 
layers  by  themselves,  for  the  inflammation  may  pass 
from  one  to  the  other  in  a  very  short  time.  Inflam- 
mation of  the  retina  may  also  extend  to  the  underly- 
ing choroid,  producing  retino-choroiditis,  and  vice 

176 


DISTORTION    OF    OBJECTS.  I  7  ^ 

versa,  inflammation  of  the  choroid  may  extend  to 
the  retina,  producing  chorio-retinitis,  but  a  simple 
inflammation  of  the  retina,  while  it  may  not  produce 
a  choroiditis  at  the  same  time,  may,  by  virtue  of  the 
retinitis,  give  the  choroid  an  unnatural  appearance, 
as  if  it  were  rough  or  granular,  spoken  of  as  "  gran- 
ular changes  in  the  choroid." 

Change  in  Visual  Acuity.  This  depends  upon 
the  part  of  the  retina  affected  and  also  upon  the 
extent  of  the  inflammation.  Central  vision  will 
remain  good  if  the  center  of  the  macula  is  not  in- 
volved or  central  vision  diminishes  in  proportion  to 
the  amount  of  involvement  of  the  macula  and  fovea. 
The  chart  for  the  field  of  vision  will  show  contrac- 
tion and  occasionally  scotomata. 

Distortion  of  Objects.  Objects  may  appear 
smaller  than  normal  (micropsia),  or  may  appear 
out  of  their  normal  shape  or  alinement  (meta- 
morphopsia),  when  the  rods  and  cones  have  been 
crowded  together  or  separated  or  changed  from 
their  normal  level  by  inflammation,  swelling  or 
exudates. 

Diagnosis.  A  positive  diagnosis  of  retinitis  is 
an  opacity  or  loss  of  transparency  of  this  mem- 
brane ;  the  other  conditions,  i.  e.,  hemorrhages,  exu- 
dates, pigmentation,  etc.,  may  add  color  to  the 
picture. 

Prognosis.  This  depends  on  the  cause,  the  part 
of  the  retina  involved,  and  the  extent  of  the  in- 
flammation. The  prognosis  is  most  favorable  when 


I  7°  THE   OPHTHALMOSCOPE. 

the  retinitis  is  due  to  syphilis  and  the  inflammation 
is  not  too  extensive  by  the  time  the  patient  comes 
under  observation.  When  the  retinitis  is  due  to 
Bright's  disease  or  diabetes  or  brain  tumor  or  men- 
ingitis the  prognosis  is  certainly  grave. 

Course  and  Complications.  Retinitis  may  be 
acute  or  chronic.  It  may  be  complicated  with  in- 
flammation of  the  choroid  (retino-choroiditis) 
(Plate  XI.)  with  inflammation  of  the  papilla 
(neuro-retinitis)  (Plate  IV.)  ;  with  inflammation 
of  the  iris  and  ciliary  body.  Eventually,  after  the 
retinitis  subsides,  the  retina  may  atrophy.  The 
central  and  peripheral  vision  in  this  disease  is  af- 
fected according  to  the  amount  and  part  of  the 
retina  involved. 

Treatment  of  Retinitis  in  General.  The  treat- 
ment of  retinitis  resolves  itself  into  the  treatment  of 
the  underlying  cause,  and  also  in  keeping  the  retina 
at  rest  by  the  use  of  a  cycloplegic  and  dark  glasses ; 
blood  letting  from  the  temples,  the  use  of  pilocarpin 
sweats,  and  attention  to  the  general  condition. 

Changes  in  the  Retina  indicative  of  disease  are 
the  following:  (i)  opacities,  (2)  edema,  (3)  exu- 
dations, (4)  hemorrhages,  (5)  pigment  changes, 
(6)  changes  in  the  vascularity,  (7)  detachment,  and 
(8)  atrophy. 

Opacities.  The  one  condition  of  the  retina  per  se 
which  is  distinctively  pathologic  is  its  loss  of  trans- 
parency commonly  spoken  of  as  opacity.  A  similar 
condition  or  loss  of  transparency,  also  spoken  of  as 


OPACITIES.  I  79 

opacity,  occurs  in  the  cornea,  lens  and  vitreous  and 
is  an  early  manifestation  of  alteration  in  any  one 
of  these  structures.  As  already  stated  the  retinal 
fibers  lying  in  front  of  the  pigment  layer  are  trans- 
parent in  health,  and  it  is  this  quality  of  losing  this 
transparency  as  an  early  manifestation  of  disease 
or  injury  that  gives  the  observer  the  opportunity  to 
make  an  early  diagnosis  of  retinitis.  The  beginner 
in  ophthalmoscopy  should  make  a  permanent  mental 
impression  of  this  and  other  facts,  to  be  mentioned 
later,  so  that  he  will  not  make  a  hasty  diagnosis  of 
retinitis  simply  because  the  eye  ground  looks  unusu- 
ally red.  An  opacity  of  the  retina  may  be  very 
slight  or  faint,  resembling  a  slight  fog  or  mist  (Plate 
II. ),  or  the  opacity  may  be  very  dense,  resembling  a 
white  cloud  (Plate  IV.),  or  the  density  of  the  opacity 
may  be  intermediate  between  these  two  extremes 
(  Plate  V. ) .  With  the  direct  method  of  examination 
there  is  no  glass  in  the  ophthalmoscope  which  will 
give  a  clear  cut  picture  of  the  fundus  at  the  place  of 
the  opacity.  Opacities  may  be  small  or  large,  just 
one,  or  a  few,  or  a  great  many ;  they  may  be  scattered 
throughout  the  retina,  or  they  may  be  quite  uniform 
and  occupy  most  of  the  retina  or  only  a  small  portion 
of  it.  It  must  also  be  borne  in  mind  that  the  retina 
is  thick  at  the  disc  and  thin  at  the  macula,  and  there- 
fore the  want  of  transparency  becomes  most  con- 
spicuous at  the  disc  when  this  is  the  portion  in- 
volved, whereas  an  opacity  at  the  macula,  which 
is  the  thinnest  part  of  the  retina,  does  not  hide  or 


l8o  THE   OPHTHALMOSCOPE. 

veil  the  underlying  structures  to  the  same  extent 
that  it  would  otherwise,  and  hence  the  macula  may 
show  as  a  crimson  spot  during  a  certain  stage  of 
retinitis  (see  Embolism  of  Central  Artery,  and 
Plate  II.).  It  has  already  been  stated  that  the 
cornea,  lens  and  vitreous  will  also  show  opacity  as 
a  pathologic  characteristic,  and  therefore  if  an 
opacity  in  one  or  all  of  these  structures  is  present 
care  must  be  taken  to  differentiate  them  as  follows : 
Opacities  of  the  cornea  and  lens  are  to  be  studied 
with  oblique  light  (Figs.  16,  17  and  18).  Diffuse 
cloudiness  of  the  vitreous  is  to  be  examined  with 
the  ophthalmoscope  and  is  seen  to  be  the  same,  no 
matter  in  which  direction  the  eye  is  turned,  and 
the  blurred  retinal  vessels  on  the  disc  and  in  the 
fundus  appear  equally  obscure  through  the  foggy 
or  opaque  vitreous.  If  the  vitreous  cloud  lies  well 
forward  in  the  vitreous,  just  back  of  the  lens,  then 
it  may  be  seen  with  the  oblique  light  and  condensing 
lens. 

In  opacity  of  the  retina,  however,  some  vessels 
may  be  focused  clearly  while  others  may  be  obscure ; 
these  latter  being  obscured  by  the  retinal  opacity 
(Plate  IV.).  The  periphery  of  the  retina  is  most 
clearly  seen  as  a  rule,  as  it  is  usually  free  from 
opacities.  It  is  well  to  remember  that  it  is  not 
impossible  to  have  opacities  of  the  cornea,  lens,  vit- 
reous and  retina  in  one  eye  at  one  and  the  same  time. 

Edema.  Edema  of  the  retina  may  be  described 
as  a  progressive  or  advanced  opacity  of  this  struc- 


EXUDATION.  l8l 

ture,  and,  like  opacity,  may  be  limited  to  a  certain 
portion  or  may  be  diffuse  throughout  the  retina. 
As  edema  means  swelling,  the  retinal  vessels  may 
be  seen  passing  over  or  through  the  edematous 
area  with  resulting  changes  in  their  appearance, 
viz.,  they  lose  their  light  streak,  appear  dark  and 
the  arteries  and  veins,  while  in  the  swollen  portion 
of  the  retina,  cannot  always  be  distinguished  from 
each  other  (Plate  V.). 

Exudation.  This  is  an  inflammatory  product, 
or  it  may  be  metastatic,  usually  circumscribed  and 
may  appear  as  small  dots  (Plate  V.),  or  as  large 
masses  covering  extensive  areas  (Plate  IV.).  The 
blood  vessels  that  pass  through  or  over  these  exu- 
dations, give  an  exaggerated  picture  of  the  condi- 
tion as  seen  in  edema.  The  periphery  of  the  eye 
ground  is  not  usually  involved  to  the  same  extent 
as  the  neighborhood  of  the  disc  (Plate  IV.).  Ex- 
udates  are  often  spoken  of  as  serous,  albuminous 
and  purulent.  The  serous  are  more  or  less  grayish 
in  color,  or  even  white  (Plate  IV.),  and  may  con- 
tain lymph  corpuscles.  The  albuminous  are  yellow 
or  yellowish-white  in  color  (Plate  V.),  and  later 
may  contain  connective  tissue.  The  purulent  exu- 
date  usually  involves  the  vitreous  to  such  an  extent 
that  unless  seen  very  early  no  view  of  the  retina 
can  be  made  out,  the  vitreous  seeming  to  be  filled 
with  a  large  yellowish  mass.  Seen  early,  small 
round  yellow  dots  would  be  recognized  in  and  about 
the  disc  and  macula. 


1 82  THE   OPHTHALMOSCOPE. 

For  a  description  of  hemorrhages,  pigment 
changes  and  changes  in  vascularity,  see  Chapter 
VII. 

Diffuse  Retinitis;  Serous  Retinitis;  Edema  of 
the  Retina;  Retinitis  Simplex.  This  may  be  en- 
tirely local  or  a  local  manifestation  of  a  constitu- 
tional disease.  As  the  name  (diffuse)  implies,  the 
inflammation  is  usually  quite  extensive  and  occupies 
a  considerable  portion  of  the  retina;  or  it  may  in- 
volve only  a  small  part  or  parts  of  the  retina  ( Plate 
V.).  One  or  both  eyes  may  be  affected.  The  in- 
flammation may  affect  the  inner  or  the  outer  layers, 
but  the  inner  layers  are  usually  the  ones  affected. 
The  ophthalmoscope  reveals  a  grayish  color  of  the 
retina;  this  may  be  very  faint,  like  a  gauzy  veil, 
or  dense  like  a  heavy  fog,  and  this  latter  obscures 
the  retinal  vessels.  The  chief  characteristic  of  this 
disease  is  the  infiltration  which  causes  the  edema 
and  opacity  of  the  retina.  The  arteries  appear 
straight  and  without  any  increase  in  size,  possibly 
they  may  be  smaller  than  normal,  whereas  the 
veins  are  increased  in  size  and  tortuous,  and  in 
severe  cases  have  an  antero-posterior  curve  (Plate 
V.).  Diffuse  retinitis  accompanies  choked  disc,  or 
any  inflammation  of  the  disc  may  show  some  fog- 
ging of  the  retina  in  its  neighborhood  or  extending 
out  from  the  disc  in  the  course  of  some  one  or  more 
of  the  larger  vessels  (Plates  III.,  V.).  Hemor- 
rhages are  not  as  common  in  diffuse  retinitis  as  in 
other  varieties  of  inflammation  of  this  structure. 


DIFFUSE   RETINITIS   OF    RETINA.  183 

When  hemorrhages  are  seen  in  diffuse  retinitis 
they  are  usually  small  and  striated  and  are  usually 
seen  in  the  course  of  the  vessels.  The  white  areas 
and  the  macular  star-shaped  figure  are  not  often 
seen  in  diffuse  retinitis;  they  are  to  be  found  in 
the  albuminuric  retinitis,  but  if  they  do  occur  in  the 
diffuse  retinitis  they  signify  that  the  outer  layers 
of  the  retina  are  involved.  Naturally,  too,  if  the 
inner  layers  of  the  retina  are  seriously  involved 
the  vitreous  soon  becomes  implicated  and  diffuse 
opacities  of  this  structure  are  seen,  and  they  in 
turn  increase  the  obscurity  of  the  retinal  picture. 

Diffuse  Retinitis  of  the  Outer  Layers  of  the 
Retina.  The  inflammation  of  these  layers  lies 
posterior  to  the  vessels  which  may  be  plainly  seen. 
The  hemorrhages  are  more  or  less  rounded  and  not 
flame-shaped.  The  exudate  is  inclined  to  be  yellow- 
ish and  not  gray.  If  the  pigment  layer  is  involved, 
then  when  the  inflammation  begins  to  subside  the 
granules  of  pigment  may  be  seen  collected  in  irregu- 
lar spots.  If  the  inflammation  extends  deeper  the 
choroid  becomes  involved  and  the  condition  is  one 
of  retino-choroiditis. 

Cause.  Exposure  to  bright  light  (snow  blind- 
ness), electric  light,  lightning,  taking  cold,  sudden 
stoppage  of  perspiration  after  violent  exercise; 
syphilis,  congenital  or  acquired.  In  some  instances 
it  is  impossible  to  find  a  cause. 

Treatment.  Rest  of  the  retina  with  cycloplegic 
and  dark  glasses,  and  treatment  of  the  cause. 


184  THE   OPHTHALMOSCOPE. 

Prognosis.  This  depends  upon  the  cause.  If 
from  syphilis  the  retinitis  may  clear  up  in  a  few 
weeks  under  energetic  specific  treatment.  When  due 
to  other  causes  the  prognosis  is  not  quite  so  favor- 
able. If  the  diffuse  retinitis  is  of  long  standing  it 
may  eventuate  in  atrophy  of  the  retina  with  marked 
failure,  in  vision;  this  latter  is  especially  true  if 
the  deep  layers  are  involved.  In  other  cases  there 
may  be  a  formation  of  new  vessels  which  are  pro- 
jected into  the  vitreous. 

Circumscribed  Retinitis.  This  is  an  inflamma- 
tion of  the  retina  which  is  limited  in  its  extent,  hence 
called  "  circumscribed."  It  is  often  seen  to  follow 
the  course  of  the  large  vessels  (Plate  V.).  Circum- 
scribed retinitis  at  the  macula,  if  in  the  deep  layers 
and  affecting  the  pigment  layer,  seriously  impairs 
central  vision  and  may  destroy  it.  A  consideration 
of  circumscribed  retinitis  is  but  a  consideration  of 
the  diffuse  variety  of  retinitis,  but  limited  in  its 
extent.  Virtually  diffuse  and  circumscribed  retin- 
itis are  therefore  one  and  the  same  disease.  The 
causes  of  each,  however,  are  not  always  the  same. 

Retinitis  Punctata.  Some  authorities  object  to 
this  name,  as  the  ophthalmoscope  does  not  reveal 
any  decided  inflammation,  and  the  same  may  be  said 
about  retinitis  pigmentosa;  however,  these  diseases 
do  have  a  low  grade  of  inflammation  as  revealed 
by  the  microscope.  As  its  name  implies  (retinitis 
punctata),  the  ophthalmoscope  reveals  many  minute 
white  or  yellowish-colored  dots,  and  these  are  best 


RETINITIS    PUNCTATA.  185 

seen  with  the  direct  method,  and  as  they  are  very 
closely  packed  together  they  give  a  stippled  appear- 
ance to  that  portion  of  the  retina  where  found, 
and  this  is  usually  between  the  macula  .and  the 
disc.  The  spots  are  not  always  in  this  location,  but 
may  be  scattered  over  the  fundus,  and  while  they 
are  usually  round  in  shape  they  may  occasionally 
appear  oval. 

These  punctate  changes  have  been  variously  de- 
scribed or  classified  and  named  by  different  ob- 
servers and  referred  to  as  "  dots  "  as  follows : 

Nettleship's  Dots.  These  dots  are  quite  small 
and  numerous,  dead  white  in  color,  not  glistening; 
they  occupy  the  space  between  macula  and  periph- 
ery, and  have  been  seen  scattered  over  the  fundus. 

Gunn's  Dots  (also  called  "  Crick's "  Dots). 
These  dots  are  quite  small  and  few  in  number,  yel- 
lowish in  color  and  occupy  the  macular  region.  A 
rare  condition,  and  found  usually  in  young  subjects. 

Retinitis  punctata  albescens  of  Mooren  resembles 
Nettleship's  dots  and  gives  night  blindness  as  a 
symptom.  The  ophthalmoscope  reveals  the  fundus 
having  many  or  a  few  white  dots  which  are  small 
and  round  in  form. 

Punctate  retinitis  is  found  in  the  eyes  of  old 
people  who  have  atheromatous  vessels,  whereas 
Gunn's  dots  are  found  in  the  eyes  of  young  patients. 

Prognosis.  Not  unfavorable  as  vision  is  not 
usually  impaired,  except  possibly  for  some  slight 


I  86  THE   OPHTHALMOSCOPE. 

contraction  in  the  field  or  for  a  moderate  amount 
of  night  blindness. 

Treatment.  Xot  benefited  by  any  treatment 
though  electricity,  alteratives,  etc.,  have  been  tried 
and  recommended. 

Apoplexy  of  Retina  (see  Plate  III.).  The  dis- 
ease under  consideration  partakes  of  the  nature  of 
a  disease  of  the  walls  of  the  vessels  and  this  so 
weakens  them  that  the  blood  corpuscles  make  their 
escape  into  the  retina,  a  condition  primarily  of  vas- 
culitis.  Retinitis  may  now  develop  from  the 
presence  of  the  blood,  the  blood  being  the  exciting 
cause  of  the  retinitis.  If  the  hemorrhage  is  a  large 
one,  or  many  smaller  hemorrhages  coalesce,  the 
intra-ocular  pressure  may  become  so  increased  as 
to  develop  acute  glaucoma  (hemorrhagic  glau- 
coma). In  apoplexy  of  the  retina  the  arteries  are 
smaller  than  normal.  This  condition  of  the  arteries 
might  lead  one  to  suppose,  that  the  hemorrhage 
was  from  a  break  in  the  vessel,  but  this  must  be  a 
mistake  as  specimens  examined  fail  to  reveal  any 
ruptures.  Hemorrhages  are  usually  from  the  large 
vessels,  therefore  they  are  seen  in  the  neighbor- 
hood of  the  disc  or  possibly  on  the  disc  itself;  these 
hemorrhages  may  be  few  or  many,  they  may  vary 
in  size  and  shape,  though  they  are  usually  quite 
large  as  compared  to  hemorrhages  occurring  in 
other  varieties  of  retinitis  (see  Plate  VI.).  Apo- 
plexy of  the  retina  is  usually  a  condition  of  the 
aged  and  often  accompanies  changes  in  the  circula- 


IIEMORRHAGIC    RETINITIS.  187 

tion  and  heart,  and  it  may  be  a  prodrome  of  cerebral 
apoplexy. 

Causes.  Usually  diseases  of  heart  and  blood 
vessels,  with  the  underlying  cause  for  the  change  in 
the  blood  and  vessel  walls,  arterio-sclerosis,  etc. 

Prognosis.    Very  unfavorable. 

Treatment.  Rest  and  treatment  of  underlying 
cause. 

Hemorrhagic  Retinitis.  Hemorrhages  in  the 
retina  without  inflammation  of  the  retina  may  be 
called  apoplexy  of  the  retina.  The  true  name  for 
hemorrhagic  retinitis  is  therefore  an  inflammation 
of  the  retina  with  accompanying  hemorrhages. 
Apoplexy  of  the  retina,  or  a  hemorrhage  in  the 
retina  will  produce  an  inflammation  of  the  retina 
and  hence  is  called  hemorrhagic  retinitis.  Apoplexy 
of  the  retina  usually  eventuates  into  hemorrhagic 
retinitis.  The  ophthalmoscope  reveals  a  cloudy 
retina  with  swollen  disc  which  has  its  edges  ob- 
scured. The  arteries  are  small  and  veins  large  and 
tortuous.  The  hemorrhages  are  many  and  varied ; 
round,  flame-shaped,  linear  and  irregular  and  ap- 
pear throughout  the  eye  ground. 

Causes.  Disease  of  heart  and  blood  vessels; 
abnormal  suppression  of  menses ;  syphilis,  etc. 

Prognosis.  This  is  usually  quite  grave  as  the 
underlying  cause  may  be  a  structural  change  in 
the  walls  of  the  vessels  or  the  heart  may  be  seri- 
ously involved.  Vision  is  liable  to  serious  and  per- 
manent injury  from  the  same  cause.  When  caused 
by  syphilis  the  prognosis  is  rather  more  favorable. 


I  88  THE    OPHTHALMOSCOPE. 

Treatment.  Rest  of  the  eye  or  eyes,  as  the  dis- 
ease may  be  monocular;  with  appropriate  treat- 
ment for  the  underlying  cause. 

Syphilitic  Retinitis.  While  syphilis  is  one  of 
the  most  common  causes  of  retinitis  it  is  interesting 
to  note  the  fact,  that  there  is  no  one  variety  of 
retinitis  that  is  typically  syphilitic.  The  nearest 
approach  to  this  is  the  diffuse  variety,  but  it  only 
proves  that  syphilis  may  be  manifest  in  the  retina 
by  affecting  the  superficial  or  deep  layers  or  it  may 
be  circumscribed,  or  the  retinitis  may  be  accom- 
panied by  choroiditis  (syphilitic  retino-choroiditis) 
(Plate  XL),  or  the  vitreous,  ciliary  body  and  iris 
may  also  be  affected  at  one  and  the  same  time,  or 
singly.  Hemorrhages  are  not  usually  the  conspicu- 
ous factors  in  syphilitic  retinitis  as  in  some  varieties 
of  retinitis,  though  they  do  occur  at  times  and  are 
often  quite  large.  The  vision  is  often  markedly 
affected  or  impaired,  depending  of  course  upon  the 
stage  of  the  disease,  its  variety  and  the  part  of  the 
eye  ground  involved. 

Course  and  Treatment.  This  disease  is  usually 
chronic.  The  treatment  of  course  is  anti-syphilitic. 
Mercurial  inunctions,  iodids  internally  and  the  use 
of  pilocarpin  sweats.  The  prognosis  depends  on 
the  stage  of  the  inflammation,  the  part  of  the  retina 
involved  and  the  persistence  and  vigor  with  which 
the  treatment  is  carried  out  and  maintained. 

Splenic  or  Leukemic  Retinitis,  Retinitis  from 
Anemia.  The  early  ophthalmoscopic  changes  of 
this  disease  are  not  unlike  those  of  diffuse  retinitis, 


PLATE   IV. 

ALBUMINURIC  RETINITIS.    RETINITIS  OF  BRIGHT'S  DISEASE.    BRIGHT'S 
RETINA.    FUNDUS  OF  RIGHT  EYE.     DIRECT  METHOD. 

Miss  K.  C.    Aged  49  years. 

History.  First  noticed  foggy  vision  in  April,  1904,  and  came  for 
examination  October  8  of  same  year,  stating  that  when  left  eye  was 
closed  objects  seen  with  right  eye  were  quite  indistinct  on  their 
left  side  (positive  scotoma). 

Vision  of  right  eye  with  +  °-5°  D-  C  +  i-SO  Cyl.  axis  180  de- 
grees =  IV/XX. 

Vision  of  left  eye  with  +  0.50  D.  C  +  J-5o  Cyl.  axis  180  de- 
grees =  IV/VIISS. 

Fundus  Changes.  Fundus  of  each  eye  very  similar,  but  that  of 
the  right  typically  marked.  Swollen  disc,  striated  edges;  exuda- 
tions ("  snow  banks  ")  about  its  edges  with  two  areas  above  and 
one  below  the  disc.  Macular  figure  unusually  well  marked.  Many 
scattered  and  flame-shaped  hemorrhages  seen  in  the  periphery  and 
about  the  disc.  Vessels  about  the  disc  show  effusion  into  their 
sheaths  by  the  white  edge  at  each  side  of  the  vessel.  The  disc 
resembles  that  of  choked  disc  in  brain  tumor,  but  the  "  snow  banks  " 
and  macular  figure  are  almost  too  conspicuous  for  such  a  diagnosis. 
The  history  of  the  patient,  not  having  any  headache,  nausea  or 
vomiting,  no  double  vision  or  any  indication  of  extra-ocular  palsies, 
excluded  the  idea  of  brain  tumor.  The  urine  analysis  confirmed 
the  kidney  changes  (interstitial  nephritis). 

Decapsulation  of  each  kidney  was  performed  February  25,  1905, 
and  patient  died  fourteen  days  later  of  uremic  coma. 


190 


PLATE    IV 


Rlbuminuric  Kstinitis 


SPLENIC    RETINITIS.  193 

but  later  on  the  fundus  may,  and  often  does,  appear 
of  a  light  orange  color,  which  authorities  recognize 
as  quite  characteristic  of  this  variety  of  retinitis, 
and  yet  there  are  cases  of  splenic  retinitis  which  do 
not  have  this  characteristic  feature.  The  veins  fre- 
quently have  an  unusual  tortuosity  and  are  quite 
distended  and  of  a  rose  red  color.  The  arteries  ap- 
pear normal  and  of  an  orange  yellow  color.  The 
disc  may  appear  normal  or  it  may  be  prominent,  and 
if  prominent  its  edges  are  hazy.  Hemorrhages 
both  large  and  small  are  seen  in  any  part  of  the 
fundus,  but  usually  about  the  equator ;  they  are  cir- 
cular in  form.  Hemorrhages  may  also  be  seen  in 
the  macular  region  and  about  the  disc.  As  the  old 
hemorrhages  disappear  new  ones  are  seen  to  make 
their  appearance.  The  hemorrhages  surround  ele- 
vated white  spots  which  vary  in  size  and  are  com- 
posed of  lymph  corpuscles. 

Treatment.    This  applies  to  the  cause. 

Renal  Retinitis,  Retinitis  of  Bright's  Disease, 
Retinitis  Nephritica,  Albuminuric  Retinitis, 
Papillo-retinitis  (Plate  IV.).  This  may  occur  in 
any  variety  of  disease  of  the  kidneys,  especially  in 
the  chronic  form,  most  frequently  with  contracted 
kidney,  also  with  the  large  white  kidney.  The 
most  common  variety  of  retinitis  is  the  neuro-retin- 
itis  (papillo-retinitis).  The  ophthalmoscope  reveals 
the  following  characteristics:  (a)  The  disc  is 
swollen  and  hyperemic  or  actively  inflamed;  (b) 
large,  round,  white  or  yellowish-white  massings  ar- 
'7 


194  THE   OPHTHALMOSCOPE. 

ranged  in  circular  form  are  seen  to  partly  or  com- 
pletely surround  the  disc;  this  is  quite  distinctive  of 
albuminuric  retinitis,  whereas  in  other  varieties 
of  retinitis  the  exudate  is  not  so  rounded  but  elon- 
gated and  follows  the  course  of  the  large  vessels. 
The  massings  around  the  disc  have  been  called 
"  snow  bank,"  and  the  name  is  obvious,  (c)  White 
spots,  small  in  size,  seen  at  the  macula  (due  to  fatty 
degeneration  of  exudates  and  retinal  elements) 
form  a  characteristic  picture  of  Bright's  disease. 
These  white  dots  appear  early  in  the  disease  and 
later  on  they  enlarge  or  coalesce  into  radiations  like 
the  spokes  of  a  wheel,  with  the  macula  as  a  center, 
their  radiations  resemble  the  points  of  a  star 
and  the  figure  has  been  called  "  stellar  "  or  "  macu- 
lar  figure " ;  this  figure  is  not  always  complete. 
However,  whether  complete  or  partial,  it  is  con- 
sidered quite  pathognomonic  of  Bright's  disease 
until  other  factors  can  be  brought  out  to  disprove 
this  diagnosis.  Therefore,  the  macular  white  dots 
are  sometimes  seen  in  other  varieties  of  inflamma- 
tion of  the  retina,  (d)  Many  of  the  retinal  vessels 
will  be  seen  to  pass  over  or  are  hidden  in  the  white 
patches.  The  arteries  appear  normal  or  smaller 
in  size,  and  the  veins  are  distended,  slightly  tortuous 
and  dark  in  color.  Arteries  and  veins  may  show 
a  white  streak  at  their  borders,  (e)  Hemorrhages 
may  occur  at  any  time  during  the  progress  of  the 
disease;  they  are  usually  in  the  nerve  fiber  layer 
and  therefore  flame-shaped.  Small  hemorrhages 


DIAGNOSIS    OF    RENAL    RETINITIS.  1 95 

in  the  deep  layers  (round-shaped  hemorrhages),  as 
an  early  manifestation,  foretell  a  most  unfavorable 
prognosis. 

Differential  Diagnosis.  Retinitis  of  Bright's 
disease  may  be  mistaken  for  retinitis  accompanying 
brain  tumor,  and  this  differentiation  is  not  always 
easy  or  positive  from  the  eye  condition  alone ;  how- 
ever, the  following  may  assist  materially  in  the 
decision. 

Bright's  Disease.  Brain  Tumor. 

Disc  usually  has  uniform  or  dif-  Disc    very    much    elevated    and 

fuse   redness  and  occasionally  vessels  seen  passing  down  into 

a  slight  swelling,  and  vessels  level  of  retina  (Plate  III.). 

buried   in  the   swelling  which 

is    not    as    prominent    as    in 

choked  disc. 

Large   vessels   show   very   little  Veins  very  large,  full  and  tortu- 

change,    the     veins     may     be  ous  very  early  in  the  disease. 

slightly  tortuous  and  darker  in 
'  color. 

Retinal  changes  appear  early.  Retinal  changes  come  late. 

White    exudates    are    numerous  White    exudates    not    so    early. 

and  coalesce ;  seen  around  disc  Macular     star     may    not    be 

and  at  the  macular  region.  present. 

Albuminuric  retinitis  rarely  affects  one  eye 
alone ;  both  eyes  are  usually  affected,  but  one  may 
be  affected  before  its  fellow. 

The  above  description  is  that  of  a  typical  case 
of  albuminuric  retinitis,  but  there  are  many  de- 
partures from  this  complete  picture;  in  fact,  the 
complete  picture  is  not  the  common  one.  There  are 
four  other  principal  pictures  of  albuminuric  retin- 
itis, described  and  named  from  a  chief  feature  seen 
in  the  fundus. 


196  THE   OPHTHALMOSCOPE. 

1.  Degenerative    Albuminuric    Retinitis.      In 
this  picture  the  whitish  ring  about  the  disc  is  ab- 
sent and  the  stellate  figure  about  the  macula  is  not 
complete.     The  disc  is   red  and  swollen  but  not 
highly  inflamed;  its  edges  are  hazy.     The  hemor- 
rhages are  nearly,  if  not  all,  flame-shaped,  occupy- 
ing the  nerve  fiber  layer. 

2.  Hemorrhagic  Retinitis  of  Bright's  Disease. 
As  its  name  implies,  this  variety  is  characterized 
by  many  hemorrhages  scattered  over  the  fundus, 
and  they  appear  as  an  early  manifestation  before 
the  disc  becomes   involved.     When   the   hemor- 
rhages are  absorbed  white  areas  take  their  places, 
and  if  the  underlying  choroid  has  been  involved, 
these  areas  may  be  partially  pigmented. 

3.  Albuminuric    Neuro-retinitis     (Plate    V.). 
Here  the  picture  is  one  of  high  grade  inflamma- 
tion of  the  disc  and  retina  with  hemorrhages  and 
exudates  as  a  consequence  of  such  inflammation. 

4.  Albuminuric  Papillitis.     The  chief  charac- 
teristic feature  here  is  the  inflammation  of  the  disc, 
giving  the  typical  "choked  disc"  (papillitis). 

Albuminuric  retinitis  occurring  during  preg- 
nancy is  the  neuro-retinitis  just  described.  The 
white  areas  are  large  and  scattered  and  due  to 
serous  effusion ;  the  hemorrhages  are  also  scattered. 
The  white  areas  do  not  usually  have  the  same  radi- 
ating figure  in  the  macula  as  in  the  typical  picture 
described  and  shown  in  Plate  IV. 

Prognosis  for  Vision.     Vision  is  usually  ma- 


PLATE    V 


lilbuminuric  Retinitis  of  Pregnancy 


PLATE  V. 

ALBUMINURIC  RETINITIS  OF   PREGNANCY.    NEURO-RETINITIS. 

PAPILLO-RETINITIS.    FUNDUS  OF  LEFT  EYE. 

DIRECT  METHOD. 

Mrs.  O.     Aged  28  years. 

Fundus  Changes.  Each  fundus  of  this  patient  showed  neuro- 
retinitis,  but  much  more  marked  in  the  left,  although  the  right  eye 
had  its  vision  destroyed  by  a  large  hemorrhage  into  the  macula. 

Vision  of  right  eye  with  +  i  D.  C  +  I-5O  Cyl.  axis  100  degrees  = 
light  perception. 

Vision  of  left  eye  with  -f-  1.50  D.  C  +  2.50  Cyl.  axis  90  degrees  = 
V/XIK?). 

The  disc  is  hidden  and  slightly  swollen,  but  not  to  the  same  ex- 
tent as  in  Plate  IV.  The  punctate  dots  above  and  at  the  macula 
(neuritic  dots)  are  quite  conspicuous.  Areas  of  exudation  are 
some  distance  from  the  disc.  The  hemorrhages  are  numerous,  small 
and  flame-shaped.  The  veins  are  full  and  tortuous  and  some  of 
them  are  covered  by  the  swollen  retina.  Patient  recovered  her 
health,  but  with  damaged  vision,  as  above  recorded,  with  her  cor- 
recting glasses.  The  following  letter  from  Dr.  Davis  is  self-ex- 
planatory and  gives  the  patient's  history : 

April  14,  1905. 
DR.  JAMES  THORINGTON, 

120  South  :8th  Street,  Phila. 

My  Dear  Dr.  Thorington:  Regarding  our  patient,  Mrs.  O.  at 
the  Polyclinic,  the  salient  points  of  the  history  are  as  follows : 

Patient,  aged  28;  multipara;  family  history,  negative;  has  had 
scarlet  fever  and  diphtheria.  No  complications  in  previous  preg- 
nancies or  labors ;  has  had  chlorosis ;  and  has  had  frequent  head- 
aches at  menstruation ;  has  worn  glasses. 

During  pregnancy  which  has  just  terminated,  felt  languid,  had 
occasional  nose-bleed  and  slight  vaginal  hemorrhage.  She  received 
no  competent  medical  care.  Her  urine  was  not  examined.  On  the 
evening  preceding  admission  to  Polyclinic  Hospital  she  felt  badly 
and  was  nauseated.  Convulsions  began  in  the  early  morning.  She 
had  eight  before  admission.  Temperature  on  admission  was  102°. 
A  convulsion  occurred  immediately  after  admission.  She  was 
treated  by  venesection  with  intravenous  transfusion  of  salt  solution, 
hot  packs  with  copious  enteroclysis.  Labor  gradually  came  on,  and 
when  the  cervix  had  softened  and  partly  dilated,  the  patient  by 
podalic  version  was  delivered  of  a  dead  7-months  child,  35  centi- 
metres long.  She  had  no  convulsion  after  delivery,  and  slowly 
regained  consciousness. 

I97 


The  placenta  was  not  examined,  nor- was  the  fetus  submitted  to 
examination. 

Examination  of  the  patient's  urine,  with  the  clinical  history  of 
her  case,  shows  that  her  eclampsia  was  the  result  of  toxemia  of 
nephritic  origin.  That  this  had  proceeded  sufficiently  far  to  pro- 
duce disintegration  of  the  red  blood  corpuscles  was  shown  by  the 
fact  that  the  patient  had  nasal  and  vaginal  hemorrhage  before  labor, 
and  also  from  the  occurrence  of  retinal  hemorrhages,  as  reported 
by  you. 

So  far  as  prognosis  for  life  is  concerned,  these  cases  are  more 
favorable  than  toxemia  of  nephritic  origin. 

This  patient  will  gradually  recover  her  usual  general  health,  and 
can  avoid  a  subsequent  toxemia,  should  pregnancy  again  occur. 

In  other  cases  which  I  have  seen,  the  eye  condition  has  gradually 
improved,  and  patients  who  were  practically  blind,  before  delivery, 
have  obtained  fair  vision. 

The  treatment  employed  in  this  case  was  that  which  I  usually 
employ  with  these  patients ;  namely,  the  abstraction  of  a  small  quan- 
tity of  blood,  followed  by  intravenous  saline  transfusion  to  neutral- 
ize poisons  circulating  in  the  blood  serum,  copious  lavage  of  the 
stomach  and  intestines,  with  perspiration  as  free  as  possible.  When 
labor  begins,  it  is  aided  and  not  allowed  to  continue  long.  Hoping 
that  these  notes  will  be  what  you  desire,  I  remain, 

Very  truly  yours, 

EDW.  P.  DAVIS. 


198 


PLATE  VI. 
RETINITIS  DIABETICA.     FUNDUS  OF  RIGHT  EYE.     DIRECT  METHOD. 

Mr.  C.  B.  E.     Aged  64  years. 

History.  Suffering  from  diabetes  for  three  years  and  sight  of 
each  eye  has  been  failing  gradually  for  the  past  three  months,  but 
within  the  last  few  days  has  not  been  able  to  read  with  any  glasses 
he  could  purchase.  Now  his  vision  is  so  defective  he  has  difficulty 
in  getting  around  the  city  and  is  afraid  of  getting  run  over. 

Fundus  Changes.  Arteriosclerosis  showing  in  the  upper  and 
lower  temporal  vessels  where  they  cross.  Small  flame-shaped  and 
round  hemorrhages  scattered  irregularly  in  the  fundus.  The  disc 
edges  are  foggy  and  the  membrana  cribrosa  is  indistinct.  The  inter- 
mediate zone  and  in  fact  the  entire  disc  has  a  canary  yellow  color 
appearance.  Fundus  of  the  left  eye  is  practically  the  same  as  the 
right. 

Vision  of  right  eye  with  -j-  i  D.  C  +  !  Cyl.  axis  180  degrees  = 
VI/XL. 

Vision  of  the  left  eye  with  same  correction  is  the  same  as  the 
right. 

Cannot  read  newspaper  print  with  any  additional  glass. 


202 


PLATE    VI 


Retinitis  Diabetica 


PROGNOSIS    FOR    PATIENTS    LIFE.  205 

terially  damaged  and  may  be  destroyed  as  the  vital 
part  of  the  eye  (the  macula)  is  seriously  involved, 
as  a  rule.  The  failing  vision  may  be  the  very  first 
symptom  which  brings  the  patient's  attention  to  his 
eyes,  and  hence  to  his  kidney  condition. 

Prognosis  for  Patient's  Life.  Most  patients 
with  albuminuric  retinitis  (except  when  due  to 
pregnancy)  die  within  two  years  (fourteen  months 
has  been  given  as  the  average)  from  the  time  the 
retinas  are  primarily  involved.  There  are  excep- 
tions to  this  statement.  The  writer  has  the  personal 
knowledge  and  has  examined  the  eyes  of  a  col- 
league's patient,  who  has  had  albuminuric  retinitis 
for  over  ten  years,  and  who  was  told  nine  years  ago 
that  he  would  not  live  another  year.  The  writer  has 
under  observation  two  cases  of  albuminuric  retinitis 
that  have  existed  for  over  two  years,  and  both  pa- 
tients are  in  fairly  good  health ;  both  these  patients 
are  syphilitic  and  have  been,  and  are  irregularly  un- 
der specific  treatment.  It  is  the  writer's  belief  and 
experience  that  syphilitic  patients,  with  albuminuric 
retinitis,  coming  under  active  specific  treatment  give 
a  much  more  favorable  prognosis  for  a  longer  life 
than  a  patient  ivho  develops  Bright's  retinitis  with- 
out this  specific  (cause?)  history. 

Treatment.  This  applies  directly  to  the  kidneys 
and  the  underlying  cause.  As  far  as  the  eyes  are 
concerned,  they  should  be  placed  at  rest  with  dark 
glasses  and  the  use  of  a  cycloplegic,  and  all  use  of 
the  eyes  at  any  near  work  must  be  stopped. 
18 


206  THE   OPHTHALMOSCOPE. 

Diabetic  Retinitis  (Plate  VI.).  Involvement  of 
the  retina  is  not  a  common  condition  in  diabetes, 
it  is  usually  a  late  manifestation,  but  when  it 
does  occur  it  is  quite  serious.  Diabetes  does, 
however,  produce  quite  marked  and  rapid  changes 
in  the  refraction  by  its  action  on  the  lens,  and 
so-called  diabetic  cataract  may  be  a  result.  The 
snow  bank  about  the  disc  and  the  macular  star  are 
usually  absent  in  diabetes.  The  hemorrhages  are 
common,  flame-shaped  and  round  and  usually  large. 
The  disc  is  not  markedly  swollen ;  late  in  the  disease 
it  may  appear  of  a  pale  yellow  color.  However, 
there  are  instances  when  diabetic  retinitis  simulates 
the  albuminuric  variety  so  closely  that  the  presence 
of  sugar  or  albumen  in  the  urine  must  settle  the 
diagnosis,  or  possibly  both  conditions  (albuminuria 
and  diabetes)  may  exist  in  the  same  subject.  Hem- 
orrhagic  retinitis  may  occur  during  diabetic  retin- 
itis. Choked  disc  may  be  present  in  diabetes,  and 
also  with  brain  tumor.  While  Bright's  disease  and 
also  diabetes  usually  affect  both  eyes  respectively 
at  the  same  time,  yet  either  may  occur  in  one  eye 
several  weeks  or  months  before  the  other  eye  is 
affected. 

Course  and  Complications.  Cataract,  inflam- 
mation of  the  iris  and  vitreous  opacities,  are  added 
complications  to  the  failing  central  and  peripheral 
vision. 

Prognosis.  Unfavorable,  depending  of  course 
upon  the  condition  of  the  disc  and  the  retinal  in- 
volvement and  complications. 


PLATE   VII. 
RETINITIS  PIGMENTOSA.    FUNDUS  OF  RIGHT  EYE.     DIRECT  METHOD. 

Mr.  S.  J.  B.     Aged  53  years.     Cigarmaker.     Englishman  by  birth. 

Vision  of  right  eye  IV/XX  with  —  2.50  D.  C  +  2-75  Cyl.  axis 
i8o=IV/X. 

Vision  of  left  eye  IV/XX  with  —  2.00  D.  C  +  2.50  Cyl.  axis  12 
degrees  =  IV/X. 

History.  So  far  as  patient  knows  has  always  had  day  sight 
(hemeralopia),  but  could  not  see  at  night  without  a  very  bright 
light,  and  has  therefore  remained  in  doors  at  night  unless  he  had 
company  after  leaving  the  house  in  the  evening.  Is  in  the  habit 
of  hurrying  home  at  twilight  and  dreads  very  dark  or  rainy  days. 
Knows  that  he  had  night  blindness  when  he  came  to  America  in 
1863,  when  about  ten  years  of  age.  His  condition  has  geen  gradu- 
ally getting  worse.  Has  tried  all  kinds  of  glasses,  but  without  much 
assistance.  This  is  proven  by  the  above  formulas.  Parents  are  not 
related  and  no  one  else  in  his  family,  so  far  as  he  knows,  has  ever 
been  similarly  afflicted.  Is  a  single  man.  Never  had  syphilis.  Has 
never  married,  as  he  was  medically  advised  not  to,  as  his  eye  con- 
dition would  very  likely  be  inherited. 

Fundus  Changes.  The  periphery  of  the  eye  ground  is  character- 
istic of  many  myopic  eyes,  the  choroidal  vessels  being  very  conspic- 
uous. The  retinal  vessels  are  not  very  numerous  and  the  smaller 
ones  can  be  traced  with  difficulty  in  the  periphery.  The  disc  is 
quite  yellow  in  color.  The  retinal  vessels  are  narrow.  The  lower 
vein  appears  large  at  first,  but  this  is  due  to  the  peculiar  way  in 
which  the  pigment  is  deposited  on  its  walls.  The  reflex  immedi- 
ately around  the  disc  approximates  the  normal,  but  beyond  this  the 
condition  is  atrophic.  A  few  stellate  pigment  spots,  together  with 
irregular  pigment  massings  on  the  vessels,  are  scattered  throughout 
the  fundus.  This  is  an  unusual  variety  of  the  disease  under  con- 
sideration. The  patient  is  color  blind  for  red.  See  chart,  Fig.  71. 


208 


PLATE    VII 


Retinitis  Pigmentasa 


RETINITIS    PIGMENTOSA.  211 

Treatment.    That  for  diabetes. 
Retinitis  Pigmentosa   (Plate  VII.),  Pigmen- 
tary Degeneration  of  the  Retina,  Night-blindness 

(Hemeralopia,  yp-epa,  day,  and  aty,  sight).  This 
disease  always  affects  both  eyes  (unless  syphilitic), 
it  begins  in  childhood  and  gradually  develops  as 
the  patient  grows  older  and  if  the  patient  lives  to 
be  sixty  years  or  more,  then  blindness  will  very 
likely  be  the  ultimate  condition.  The  cause  of  this 
peculiar  disease  is  unknown,  though  statistics  re- 
veal the  fact  that  about  one  case  in  three  can  be 
traced  to  consanguinity  of  the  parents.  Syphilis, 
congenital  or  acquired,  is  also  a  cause. 

Pathology.  The  connective  tissue  of  the  entire 
retina  becomes  thickened  or  hypertrophied  and  the 
nerve  elements  atrophic  (degenerated),  this  latter 
gradually  reducing  visual  acuity.  The  caliber  of 
the  retinal  vessels  becomes  narrowed  by  direct  thick- 
ening of  their  walls  and  the  diameter  of  the  ves- 
sels gradually  diminishes  also.  The  retinal  pig- 
mentation becomes  disturbed,  and  in  a  most 
peculiar  manner  and  one  that  has  never  been 
satisfactorily  explained. 

Ophthalmoscopic  Findings.  The  pigmentation 
appears  in  masses  or  patches  and  is  deposited  in  the 
retina  and  it  not  only  follows  the  course  of  the 
retinal  vessels  but  forms  on  the  vessel  walls;  this 
is  quite  a  diagnostic  feature  of  the  disease.  In 
childhood  or  in  the  early  stages  of  the  disease  this 
pigmentation  is  seen  only  in  the  periphery  of  the 


212 


THE   OPHTHALMOSCOPE. 


eye  ground  but  later  on  these  spots  increase  in 
numbers  and  unite,  sending  off  filiform  processes, 
so  that  they  resemble  bone  corpuscles,  and  are  often 
star-shaped,  and  there  may  be  other  pigment  mass- 
ings  present  which  are  most  irregular  and  may  have 
a  spider-shaped  formation,  so  that  the  retina  in 
some  instances  looks  as  if  it  had  a  black  network 
or  irregularly  folded  veil  stretched  over  it.  This 


FIG.  71. — Form  Field,  showing  contraction  in  all  meridians.  This  is 
the  chart  of  the  right  eye  of  the  patient  with  Retinitis  Pigmentosa,  as 
illustrated  in  Plate  VII.  The  outer  edge  of  the  black  area  represents  the 
normal  field  and  the  inner  edge  of  the  black  area  shows  the  contraction. 

whole  process  of  pigmentation  begins  well  forward 
and  gradually  extends  inward  toward  the  disc 
in  a  uniform  manner.  When  seen  in  childhood 
this  process  of  pigmentation  is  not  well  developed 
but  progresses  slowly  as  the  patient  grows,  unless 
some  intercurrent  disease  develops  when  the  pig- 


RETINITIS    PIGMENTOSA.  213 

mentation  may  be  hastened.  One  case  under  the 
writer's  observation  (the  parents  of  the  patient  were 
second  cousins)  developed  dorsal  curvature  of  the 
spine  and  the  retinal  disease  increased  rapidly.  The 
disc  gradually  loses  its  normal  appearance  and 
takes  on  a  yellowish-gray  color  and  may  eventually 
become  white,  atrophic.  Cases  of  retinitis  pigmen- 
tosa  are  often  complicated  with  posterior  polar 
cataract  and  nystagmus,  especially  when  congenital. 
See  description  for  Plate  VII. 

Subjective  Symptoms.  The  chief  characteris- 
tic symptom,  and  the  one  by  which  the  patient's 
attention  is  first  called  to  his  condition,  is  the  in- 
ability to  see  distinctly  when  twilight  begins  or 
after  the  sun  goes  down.  He  may  see  perfectly 
well  in  day  time  so  far  as  he  knows,  but  after  dark 
he  will  stumble  and  bump  into  objects. 

Field  of  Vision.  The  field  of  vision  becomes 
more  and  more  contracted  as  the  disease  progresses 
and  atrophy  develops  (Fig.  71). 

Central  Vision.  This  remains  good  much  longer 
than  peripheral  vision,  but  the  condition  means  ulti- 
mate blindness  if  the  patient  survives.  The  re- 
fractive error  is  not  known  to  influence  the  suscepti- 
bility of  an  eye  to  the  disease  under  consideration. 
Many  illustrated  cases  would  indicate  that  the  eyes 
were  hypermetropic  and  yet  the  fundus  shown  in 
Plate  VII.  happened  to  be  in  a  stretching  myopic 
eye  that  had  the  choroidal  circulation  very  much 
exposed  in  the  periphery. 


214  THE    OPHTHALMOSCOPE. 

Differential  Diagnosis.  Retinitis  pigmentosa  is 
not  a  common  disease  and  ordinarily  it  is  easily 
differentiated  from  choroiditis  or  retino-choroiditis 
which  it  is  said  to  somewhat  resemble. 

Retinitis  Pigmentosa  Retino-choroiditis 

(Plate  VII.).  (Plate  XL). 

Choroidal  changes  often  absent.  Choroidal  changes  present. 

Pigment    spots    not    round,    but  Pigment  spots  are  round  or  in 

stellate.  form    of    rings    or    irregular 

shapes. 

Pigment  follows  course  of  ves-  Pigment  does  not  follow  course 

sels  and  often  seen  on  top  of  of  vessels  to  any  great  extent, 
vessels. 

Treatment  of  Retinitis  Pigmentosa.     If  due 

to  syphilis,  iodids  and  mercury  should  be  ordered. 
For  the  congenital  variety  strychnia  and  galvanism 
should  be  tried,  though  the  prognosis  in  such  cases 
is  very  grave. 

Sclerosis  of  the  Retina.  Called  also  non-pig- 
mented  sclerosis.  This  is  another  variety  of  retin- 
itis  which  gives  a  contracted  field  and  blindness  at 
night ;  the  same  symptoms  are  obtained  as  in  retinitis 
pigmentosa,  therefore  these  two  diseases  markedly 
resemble  each  other,  but  the  ophthalmoscope  does 
not  reveal  the  typical  pigmentation  just  described, 
but  rather  a  pale  fundus  or  one  resembling  a  slow 
or  low  grade  of  inflammation  of  the  retina,  and 
choroid,  with  here  and  there  scattered  dots  of  pig- 
ment. Several  members  of  the  same  family  may 
have  the  condition,  which  suggests  that  it  is  con- 
genital and  possibly  due  to  consanguinity  of  the 
parents.  There  is  no  treatment  of  any  avail. 


PLATE   VIII. 

PARTIAL  DETACHMENT  OF  THE  RETINA.    FUNDUS  OF  THE  RIGHT  EYE. 
DIRECT  METHOD. 

Mr.  M.  Aged  46  years.  Patient  seen  in  consultation  by  Dr.  G. 
E.  de  Schweinitz. 

History  of  Myopia.  Always  carefully  refracted.  Was  struck  on 
the  left  side  of  the  head  some  few  days  before  coming  under  obser- 
vation. 

Fundus  Changes.  Retina  detached  downward  and  forward.  The 
wavy  condition  of  the  retina,  the  course  of  the  dark-colored  vessels 
without  their  usual  light  streaks,  as  they  appear  on  the  detachment, 
are  all  quite  characteristic  of  the  condition  under  consideration. 
The  disc  appears  foggy  because  it  is  out  of  focus  as  compared  with 
the  detachment,  which  is  in  focus  for  purpose  of  sketching.  The 
disc  is  seen  with  —  7  D.,  whereas  the  detachment  is  best  seen  with 
a  +  I  D-  Two  most  peculiar  and  irregular  white  streaks  with  pig- 
ment massings  on  their  upper  edges  are  seen  down  and  out  and 
down  and  in,  beginning  a  short  distance  from  the  disc  and  extend- 
ing as  far  forward  as  the  eye  can  see  into  the  periphery.  These 
white  streaks  resemble  obliterated  vessels  or  ruptures  in  the  choroid, 
and  what  is  still  more  peculiar  each  eye  has  the  same  condition 
and  in  about  the  same  situation.  There  is  no  detachment  in  the 
left  eye.  The  white  streaks  are  very  likely  congenital  and  possibly 
obliterated  vessels.  A  rupture  of  the  choroid  would  be  crescentic 
in  shape  and  situated  elsewhere  in  the  fundus,  and  it  is  not  likely 
that  there  would  be  two  ruptures  in  the  same  eye  or  in  both  eyes. 
Each  eye  has  compound  myopic  astigmatism. 

See  chart,  Fig.  72. 

Vision  of  right  eye  IV/L  with  —  5.25  D.  C  —  1-25  Cyl.  axis  20 
degrees  =  l°  prism  b.  d.  ==  VI/VI. 

Vision  of  left  eye  IV/CXX  with  —  8.25  D.  Z  —  3-25  Cyl.  axis 
165  degrees  =  i°  prism  b.  up.  =  VI/VI. 


216 


PLATE    VIM 


Detachment  of  the  Retina 


OPHTI-IALMOSCOPIC    FINDINGS.  2IQ 

Detachment  of  the  Retina.  This  means  that 
the  retina  is  no  longer  held  up  against  the  choroid 
by  the  vitreous,  the  latter  having  become  diseased 
or  some  force  greater  than  the  vitreous  pressure,  has 
been  exerted  from  behind  and  the  retina  has  come 
forward  as  a  consequence.  This  may  occur  in  any 
part  of  the  retina  either  as  a  partial  condition 
(Plate  VIII.)  or  as  a  total  detachment;  this  latter 
is  sometimes  spoken  of  as  an  umbrella  detachment, 
in  its  resemblance  to  a  closed  umbrella,  the  retina 
remaining  attached  at  the  disc  edges  and  the  ora 
serrata. 

Ophthalmoscopic  Findings.  Viewing  a  fundus 
having  a  partial  detachment,  the  normal  reflex  is 
absent  at  the  portion  detached  and  in  its  place  is 
seen  a  reflex  more  or  less  opaque  and  gray  in  color 
with  its  surface  uneven  and  more  or  less  wavy.  The 
retinal  vessels  passing  over  the  detachment  are  quite 
dark,  or  blue-black  in  color,  and  have  lost  their 
light  streak,  they  have  peculiar  positions  or  curves 
or  bends  which  are  in  keeping  with  the  surface  of 
the  detachment,  they  appear  decidedly  serpentine. 
The  same  lens  in  the  ophthalmoscope  will  not  focus 
the  same  or  any  one  vessel  in  all  of  its  various  posi- 
tions. If  the  eyeball  is  rotated  in  different  direc- 
tions the  detachment  with  its  vessels  are  seen  to 
move  according  to  the  fluidity  of  the  vitreous  and 
underlying  fluid.  When  the  retina  is  totally  de- 
tached, no  view  of  the  interior  of  the  eye  can  be  ob- 
tained and  the  condition  can  best  be  examined  by 


22O 


THE    OPHTHALMOSCOPE. 


having  the  pupil  dilated  and  using  the  oblique 
light.  Detachment  usually  affects  one  eye  alone, 
though  both  eyes  may  become  affected,  one  eye 
before  the  other;  seldom  are  both  eyes  affected 
primarily  at  the  same  time  unless  from  injury. 
Occasionally  it  is  the  upper  part  of  the  retina  that 
detaches  first  and  the  fluid  behind  gradually 
gravitates  downward  and  in  this  way  the  part  first 
detached  may  settle  back  to  its  normal  position  and 


FIG.  72. — Form  Field,  showing  the  upper  field  cut  off  abruptly  and  also 
considerable  contraction  down  and  out.  This  is  the  chart  of  the  patient 
with  Partial  Detachment  of  the  retina  in  right  eye,  as  illustrated  in 
Plate  VIII. 

the  lower  part  becomes  the  detached  portion.  The 
detached  retina  soon  becomes  blind.  Sooner  or 
later,  depending  upon  the  amount  of  the  detach- 
ment, the  lens  becomes  opaque  and  the  eyeball  re- 
mains quite  soft. 


CAUSES    OF    DETACHMENT.  221 

I 

Visual  acuity  is  not  materially  interfered  with 
unless  the  detachment  is  very  large  or  involves 
the  macular  region  or  the  vitreous  or  lens  become 
cloudy.  The  field  of  vision  is  lost  in  the  area  cor- 
responding to  the  detachment,  and  it  is  often  this 
one  symptom  which  brings  the  patient  under  ob- 
servation (see  Chart,  Fig.  72). 

Causes  of  Detachment.  The  most  common 
cause  is  myopia  (the  stretching  eyeball).  Other 
causes  are  inflammation  of  the  retina;  or  ciliary 
body;  or  uveitis;  cysticercus;  injuries;  tumors  of 
the  choroid;  diminished  intra-ocular  tension  fol- 
lowing the  removal  of  the  lens  on  account  of  high 
myopia,  loss  of  vitreous  from  any  cause  and  also 
diminution  in  the  density  of  the  vitreous  as  seen  in 
diabetes,  etc.,  and  also  from  a  pulling  on  the  retina 
by  cicatricial  bands.  Detachment  of  the  retina  may 
develop  suddenly  from  straining  at  stool  or  after 
stooping  over  or  after  running  or  after  any  great 
exertion.  A  patient  of  the  writer's  developed  or 
noticed  sudden  loss  of  sight  in  the  lower  field  after 
a  violent  spell  of  sneezing  and  a  detachment  was 
carefully  studied  and  mapped  out  two  hours  later. 
Retinal  detachment  is  said  to  be  much  more  common 
among  men  than  women. 

Differential  Diagnosis.  Detachment  due  to 
fluid  and  that  due  to  a  neoplasm  should  have  careful 
consideration  as  bearing  upon  the  life  of  the  pa- 
tient. A  growth  beneath  the  retina  would  give  a 
somewhat  similar  picture  to  that  of  detachment  as 


222  THE    OPHTHALMOSCOPE. 

far  as  the  curves  in  the  vessels  are  concerned,  but 
they  would  very  likely  maintain  their  light  streak 
which  they  would  not  do  in  a  fluid  detachment,  and 
there  would  not  be  that  wavy  appearance  to  the 
retina  and  vessels  as  in  the  fluid  detachment,  neither 
would  there  be  that  motion  to  the  detachment  when 
the  eyeball  was  suddenly  rotated,  and  furthermore 
when  the  retina  is  raised  up  by  a  growth  from  the 
choroid  it  has  more  definite  or  sharply  cut  edges, 
as  compared  to  a  detachment  from  fluid. 

Elevation  of  the  Detachment.  The  detachment 
of  the  retina  whether  due  to  fluid  or  a  growth  means, 
that  the  retina  in  the  area  of  detachment  is  brought 
closer  to  the  crystalline  lens,  and  therefore  to  study 
or  examine  it  carefully  a  much  stronger  plus  lens 
must  be  employed  at  the  sight-hole  of  the  ophthal- 
moscope if  the  eye  is  naturally  hypermetropic  than 
would  be  required  to  see  the  disc,  and  if  the  eye 
was  myopic  then  a  weaker  minus  lens  or  very  likely 
a  plus  lens  would  have  to  be  employed  to  see  the 
vessels  on  the  detachment.  The  difference  in  the 
strength  of  the  lenses  employed  to  see  the  surround- 
ing attached  retina  and  the  top  of  the  detachment 
represents  the  amount  of  the  elevation,  depending 
of  course  upon  the  position  of  the  growth  or  loose 
retina,  whether  well  forward  in  the  eye  ground  or 
back  near  the  disc.  Every  three  diopters  of  differ- 
ence represents  one  millimeter  of  elevation.  The 
field  of  vision  and  the  elevation  carefully  studied 
at  different  times  and  then  compared,  will  be  a 


TREATMENT   OF   DETACHMENT.  223 

guide  as  to  the  increase  or  decrease  in  size  of  the 
detachment  or  growth. 

Prognosis.  Most  unfavorable  for  permanent 
reattachment.  Usually  the  detachment  becomes 
complete  and  sight  destroyed. 

Treatment.  Enucleation  of  the  eye,  if  the  de- 
tachment is  due  to  a  growing  tumor.  If  due  to 
fluid,  and  the  patient  comes  under  observation  quite 
early,  then  the  patient  must  be  placed  in  the  recum- 
bent position,  atropin  instilled  and  the  eye  gently 
bandaged.  The  patient  must  be  freely  purged  and 
following  this  pilocarpin  sweats  must  be  given 
every  night  or  every  other  night,  according  to  the 
patient's  condition  and  according  to  the  changes 
whch  take  place  in  the  eye.  Subconjunctival  injec- 
tions of  normal  salt  solution  should  be  given  every 
second  or  third  day.  Internally  the  patient  should 
receive  increasing  doses  of  the  iodid  of  potash.  The 
eye  ground  should  be  studied  briefly  each  day  to  see 
if  the  fluid  is  diminishing  and  the  retina  resuming 
its  normal  position;  when  this  has  been  accom- 
plished the  patient  should  remain  comparatively 
quiet  for  several  days  before  attempting  any  move- 
ments like  walking  up  and  down  stairs.  The  treat- 
ment by  tapping  the  fluid  through  the  scleral  coat 
and  drawing  off  the  fluid,  and  then  injecting  irri- 
tants like  the  tincture  of  iodin,  etc.,  is  not  considered 
advisable ;  all  such  treatment  has  been  tried  and  ulti- 
mate failures  reported.  Most  every  case  treated 
has  failed  of  permanent  reattachment,  yet  as  some 


224  THE    OPHTHALMOSCOPE. 

few  recoveries  have  been  reported,  the  treatment 
should  be  carried  out  in  each  case,  especially  if  seen 
quite  early ;  the  earlier  the  case  comes  under  obser- 
vation the  better. 

Rupture  of  the  Retina.  This  is  a  most  unusual 
condition,  though  it  has  been  recognized.  A  rup- 
ture of  the  retina  accompanying  a  corresponding 
condition  of  the  choroid  is  not  so  infrequent.  If 
the  retina  is  ruptured  its  ragged  edges  will  be  seen 
and  also  the  exposed  choroid  beneath;  of  course 
if  a  hemorrhage  occurs  at  the  time  of  the  rupture 
then  the  wound  may  be  covered,  but  as  soon  as  the 
hemorrhage  is  absorbed  the  diagnosis  can  be  made. 
The  retina  is  liable  to  rupture  after  being  detached, 
therefore  it  may  be  a  sequela  of  detachment  of  the 
retina. 

Commotio  Retinae,  or  Contusion  of  the  Retina. 
A  severe  blow  upon  the  eyeball  or  the  head  with  a 
blunt  instrument  such  as  a  ball,  club,  fist,  etc.,  will 
produce  impaired  vision,  redness  of  the  eyeball,  and 
dread  of  light  (photophobia).  These  symptoms 
will  ordinarily  pass  away  in  a  few  hours  unless 
unusually  severe.  For  the  time  being,  however,  the 
ophthalmoscope  reveals  a  slight  opacity  of  the 
retina.  A  guarded  prognosis  should  be  given,  for 
if  the  condition  persists  for  some  time,  it  may 
eventuate  in  impaired  vision  which  may  become 
permanent. 

Glioma  of  the  Retina  (also  called  "  Amaurotic 
Cat's  Eye).  This  is  a  disease  of  the  retina  which 


GLIOMA    OF    RETINA.  225 

occurs  in  infancy,  very  seldom  after  the  age  of  six 
years,  though  a  case  has  been  reported  which  oc- 
curred as  late  as  twelve  years.  Glioma  is  therefore 
recognized  as  a  disease  of  infancy,  a  congenital  con- 
dition, and  has  been  known  to  affect  more  than  one 
child  in  the  same  family.  It  usually  affects  one  eye, 
but  may  appear  in  both.  "  Glioma  is  the  only  neo- 
plasm which  occurs  in  the  retina."  (Fuchs.)  Gli- 
oma is  a  non-pigmented  growth  springing  from  the 
inner  granular  layer  of  the  retina,  and  grows  rap- 
idly. The  child  is  usually  brought  under  observa- 
tion with  the  statement  from  the  mother  or  some 
member  of  the  family,  that  a  glistening  reflex  from 
the  eye  has  been  noticed  for  a  certain  length  of 
time  and  that  the  child  did  not  appear  to  be  seeing 
with  the  eye  or  on  the  side  corresponding  to  the 
eye  affected.  Hence  the  name  amaurotic  (d/taupd?, 
dark  or  blind). 

Ophthalmoscopic  Findings.  No  definite  fun- 
dus  reflex  can  be  made  out  unless  the  eye  is 
brought  under  observation  quite  early,  but  no 
matter  whether  seen  early  or  in  the  late  stage  of 
the  disease,  it  will  be  necessary  to  examine  the  eye 
with  the  oblique  light  and  have  the  pupil  dilated. 
The  glioma  is  usually  of  a  whitish-pink  color  and 
may  be  irregular,  lobulated  or  smooth. 

Growth  of  the  Glioma.  This  is  quite  rapid  as  a 
rule,  and  especially  so  after  the  first  stage  which  is 
that  of  loss  of  sight  and  increase  of  tension;  then 
comes  great  pain  and  the  growth  perforates  the 


226  THE    OPHTHALMOSCOPE. 

eye  in  different  places,  usually  at  the  nerve  and  the 
edge  of  the  cornea.  The  orbit  becomes  crowded 
and  the  bleeding  mass  protrudes  between  the  lids 
and  onto  the  cheek.  By  metastasis  and  continuity 
of  structure,  the  disease  spreads  to  the  internal 
organs  and  the  brain.  The  patient  wastes  away 
and  dies. 

Differential  Diagnosis.  Glioma  resembles 
pseudo-glioma  (purulent  choroiditis)  which  is  not 
a  malignant  disease.  It  also  resembles  tubercle  of 
the  choroid  (see  choroidal  diseases). 

Glioma.  Pscudo-Glioma. 

Pinkish-white  color.  Yellow  or  straw  color. 

Smooth  or  tabulated  surface.  Flat  surface. 

Iris  usually  pushed  forward.  Iris  adherent  posteriorly  in  most 

instances,  and  its  ciliary  bor- 
der retracted. 

Anterior  chamber  shallow.  Deep  anterior  chamber. 

May  appear  vascular.  Does  not  appear  vascular. 

Tension  may  be  very  much  in-    x  Tension  diminished, 
creased. 

Prognosis.  Unfavorable  unless  the  eye  is 
enucleated  early.  The  prognosis  is  favorable,  if 
the  glioma  does  not  return  within  three  years  after 
removal. 

Treatment.  Early  enucleation  and  dividing  the 
nerve  as  far  back  as  possible. 

Retinitis  Circinata  (Described  by  Fuchs).  The 
retinal  picture  of  this  disease  as  seen  with  the  oph- 
thalmoscope is  that  of  a  number  of  glistening  white 
patches  which  are  arranged  in  the  form  of  an  oval 
about  the  macula,  extending  well  upward  and 


AMAUROTIC    FAMILY    IDIOCY.  227 

downward  almost  to  the  temporal  vessels.  Occa- 
sionally the  retinal  vessels  are  seen  to  pass  over 
these  white  patches  which  resemble  the  patches  seen 
in  albuminuric  retinitis  and  diabetes.  Occasion- 
ally a  few  hemorrhages  are  seen  in  the  white 
areas.  The  macula  is  usually  involved  and  its 
visual  quality  is  very  much  reduced.  This 
seems  to  be  a  disease  of  the  macular  region,  as  the 
rest  of  the  eye  ground  appears  normal.  For- 
tunately, this  is  a  rare  disease  and  is  usually  found 
among  the  aged.  There  is  no  relief  for  the  condi- 
tion and  fortunately  total  blindness  seldom  occurs. 
Amaurotic  Family  Idiocy,  Symmetric  Changes 
at  the  Macula  Lutea  in  Infancy.  The  infant  is 
usually  of  Hebrew  parentage.  A  most  unusual 
disease  and  not  many  cases  recorded.  It  was  first 
described  by  Warren  Tay.  The  ophthalmoscopic 
picture  is  one  which  resembles  embolism  of  the  cen- 
tral artery.  In  this  disease  the  macula  lutea  is 
very  conspicuous  by  being  cherry  red  and  of  much 
larger  area  than  the  red  spot  of  embolism ;  it  is  im- 
mediately surrounded  by  an  area  of  gray  white- 
ness about  the  size  of  the  disc  or  a  trifle  larger. 
The  rest  of  the  eye  ground  appears  normal,  all 
except  the  disc,  which  soon  becomes  atrophic.  As 
its  name  indicates,  it  is  a  disease  of  infancy.  The 
infant  seldom  reaches  its  third  year.  Disease  of 
the  brain  and  spinal  cord  accompany  the  eye  condi- 
tion. This  disease  is  caused  by  an  arrest  of  devel- 
opment and  changes  are  found  in  the  ganglion 


228  THE   OPHTHALMOSCOPE. 

cells  of  the  retina,  of  the  cortex,  and  degeneration 
of  the  cord. 

Purulent  Retinitis.  This,  like  purulent  choroid- 
itis,  is  due  to  septic  emboli,  and  the  two  conditions 
generally  appear  together.  The  ophthalmoscope 
shows  numerous  hemorrhages  and  many  white  or 
yellowish-white  opaque  spots,  which  soon  become 
diffuse  and  the  vitreous  becomes  cloudy  (see  Puru- 
lent Choroiditis). 

Angioid  Streaks.  Pigment  streaks  in  the  retina. 
This  is  a  very  rare  condition  affecting  both  retinas. 
The  vision  is  somewhat  diminished.  These  streaks 
are  recognized  as  being  in  the  deep  layers  of  the 
retina,  as  the  retinal  vessels  are  seen  to  pass  over 
them.  The  first  impression  is,  that  these  streaks  are 
obliterated  vessels  which  they  resemble.  They  are 
brownish  in  color,  irregular  in  outline  and  not  sym- 
metric. There  is  no  treatment. 


CHAPTER    IX. 

DISEASES  OF  THE  OPTIC  NERVE. 

DISEASES  of  the  optic  nerve  are  recognized  by 
the  patient's  symptoms,  the  field  of  vision,  the 
visual  acuity  and  a  study  of  the  optic  disc  which 
is  the  only  part  of  the  nerve  that  can  be  seen  with 
the  ophthalmoscope.  The  study  of  the  pathologic 
disc  therefore  requires  a  knowledge  and  apprecia- 
tion of  the  normal  disc  and  an  intimate  acquaint- 
ance with  the  anatomic  construction  of  the  part 
and  parts  concerned  (see  Chapter  III.).  The 
disc  itself  is  nourished  by  the  capillary  branches 
from  the  central  and  posterior  ciliary  arteries 
which  make  up  the  circle  of  Haller.  The  central 
vessels  (except  the  capillaries  just  mentioned)  on 
the  disc  are  terminal  vessels  and  go  to  nourish  the 
retina.  The  transparent  nerve  fibers  in  their  re- 
spective bundles  pass  through  the  openings  in  the 
membrana  cribrosa ;  these  openings  act  like  so  many 
collars  around  the  nerve  bundles,  if  therefore  from 
any  cause  these  nerve  fibers  become  swollen  or  in- 
flamed, then  the  membrana  cribrosa  acts  like  liga- 
tures and  the  resulting  conditions  as  seen  with  the 
ophthalmoscope  must  be  in  keeping  with  the  degree 
of  swelling  and  constriction  exerted. 

Color  of  the  Normal  Disc.  This  has  already 

229 


230  THE   OPHTHALMOSCOPE. 

been  described  in  Chapter  IV.,  but  there  is  ample 
room  for  dispute  by  the  best  authorities  as  to  slight 
changes  from  the  normal  complexion  or  what  repre- 
sents the  normal  color  for  a  certain  disc  in  a  cer- 
tain fundus,  and  frequently  the  surgeon  must  make 
examinations  on  different  days  before  committing 
himself  to  an  opinion  that  might  otherwise  be 
erroneous. 

Hyperemia  of  the  Disc.  The  normal  disc  is 
said  to  be  pink  or  yellowish-red  in  color  (Plate  I.)  ; 
then  if  the  disc  appears  red  in  color  it  is  said  to  be 
hyperemic;  some  authorities  call  this  "peach  red," 
"  cinnabar  red,"  "  brick  dust  red,"  etc.  If  the 
hyperemia  is  of  moderate  amount  the  edge  of  the 
disc  may  be  easily  distinguished,  but  if  the  hyper- 
emia is  excessive  or  is  increasing,  the  disc  becomes 
indistinct  or  possibly  obscured,  and  the  disc  edges 
cannot  be  definitely  distinguished  from  the  sur- 
rounding eye  ground  except  by  following  the  ves- 
sels to  their  central  convergence. 

Pallor  of  the  Disc.  This  is  a  condition  the  very 
reverse  of  hyperemia.  The  color  of  the  disc  in  place 
of  being  normal  in  color  will  appear  chalky  white, 
as  the  very  extreme  condition  of  pallor.  Slight 
degrees  of  pallor  are  not  readily  distinguished, 
and  considerable  practice  is  required  for  a  positive 
opinion,  and  frequently  other  conditions  must  be 
taken  into  consideration  before  deciding  positively. 
Pallor  of  the  disc  due  to  anemia  gives  the  rest  of 
the  eye  ground  a  pale  appearance  also,  whereas 


DEPRESSIONS   OF   DISC.  231 

when  the  disc  is  chalky  white  in  color,  the  surround- 
ing eye  ground  appears  redder  than  normal,  and 
this  is  brought  about  by  contrast  (Plate  X.). 

Changes  or  Alterations  in  the  Surface  Level 
of  the  Disc,  as  compared  with  the  adjacent  eye 
ground.  The  disc  may  appear  level  with  the  sur- 
rounding eye  ground  or  depressed  in  whole  or  in 
part,  or  it  may  appear  elevated. 

Depressions.  These  may  be  classed  as  three, 
the  physiologic  cupping,  the  glaucoma  cup  and  the 
depression  from  atrophy  (saucer  cupping).  This 
term  'saucer  cupping'  is  really  a  misnomer,  and 
saucer  excavation  is  a  better  one. 

In  the  study  of  an  elevation  or  depression  of  the 
disc  three  methods  may  be  followed:  first,  the  ves- 
sels are  carefully  studied  in  their  course  as  they 
adapt  themselves  to  the  surface  on  which  they  lie. 
As  an  elevation  or  depression  is  a  gradual  ascent  or 
descent,  then  the  course  of  the  vessel  will  appear 
gradually  changed,  whereas,  if  the  elevation  or  de- 
pression is  abrupt  the  course  of  the  vessel  will  appear 
more  or  less  sharply  bent.  If  the  alteration  from 
the  level  is  gradual,  then  the  vessel  may  be  continu- 
ously traced,  but  if  the  alteration  from  the  level  is 
abrupt  the  vessel  will  have  the  appearance  of  being 
broken,  or  it  appears  to  stop  abruptly  and  then  to  start 
again  at  a  different  level  (Plate  XIL).  Second,  the 
proof  of  the  difference  in  level  is  made  evident  when 
the  observer  has  to  employ  a  different  strength  lens 
in  the  ophthalmoscope  to  see  the  vessel  clearly  in 


232  THE   OPHTHALMOSCOPE. 

its  different  positions  or  levels ;  for  instance,  a  ves- 
sel at  the  edge  of  the  disc  may  be  seen  clearly  with 
a  +  5  D.  in  the  ophthalmoscope,  and  at  the  same 
time  the  same  vessel  will  appear  hazy  or  indistinct 
at  the  bottom  of  the  cupping,  and  might  require  a 
minus  lens  to  bring  it  into  view  at  that  point.  It  is 
much  better  to  select  small  vessels  for  this  test  as 
they  usually  lie  closer  to  the  surface,  and  at  the 
same  time  require  a  little  more  delicate  focusing. 
Third,  the  parallax  test  (Chapter  IV.). 

1.  Physiologic   Cupping    (see    Chapter    IV.)- 
Fig.  73,  No.  i,  is  a  drawing  of  the  disc,  showing 
physiologic  cupping,  and  illustrates  the  manner  in 
which  the  vessels  pass  in  and  out  of  it,  conveying 
the  idea  of  how  the  nerve  level  is  depressed  with 
the  cupping. 

2.  Depression  from  Glaucoma  Cupping  (Plate 
XII. ).     This  cupping  represents  an  excavation  of 
the  entire  nerve  head  or  disc,  and  is  produced  by 
intra-ocular  pressure;  in  other  words,  the  nerve 
head  is  pressed  backward  into  the  scleral  ring.    The 
edge  of  the  cup  is  steep,  precipitous  and  even  over- 
hanging.    The  disc  varies  in  color  in  different 
cases,   and  is  therefore  variously   described   as 
greenish,  gray,  grayish-blue  or  white.    The  vessels 
in  the  retina  appear  to  stop  suddenly  as  they  pass 
over  the  edge  into  the  cup,  and  then  may  reappear 
out  of  focus  at  the  bottom  of  the  cup.    The  arteries 
are  smaller  in  caliber  and  the  veins  are  full  and  tor- 
tuous, sometimes  having  the  appearance  of  a  string 


DEPRESSION    FROM    GLAUCOMA    CUPPING.       233 

of  beads.  When  the  edge  of  the  disc  is  clearly  fo- 
cused and  the  ophthalmoscope  is  tilted  so  that  the  re- 
flected light  passes  across  the  disc,  the  bottom  of  the 
cupping  appears  to  have  a  different  rate  of  move- 


ment; this  is  called  the  glaucomatous  parallax. 
Plate  XII.  shows  the  apparent  sudden  termination 
of  the  retinal  vessel  at  the  edge  of  the  disc,  and 
also  the  same  vessel  dimly  seen  in  the  bottom  of  the 


20 


234  THE    OPHTHALMOSCOPE. 

cupping.  Fig.  73,  No.  3,  is  a  section  of  a  glaucoma- 
tous  cupping  and  shows  the  steep  or  overhanging 
walls  of  the  cup. 

3.  Depression  of  the  Disc  from  Atrophy.  This 
form  of  depression,  like  the  glaucomatous,  extends 
over  or  embraces  the  entire  disc,  but  unlike  the  glau- 
comatous, it  is  shallow  and  the  depression  is  very 
gradual  from  edge  to  center,  not  abrupt  like  a  cup, 
but  gradual  like  a  saucer ;  hence  it  is  spoken  of  as  a 
saucer  excavation  in  contradistinction  to  the  cup- 
ping excavation.  The  vessels  on  the  disc,  there- 
fore, do  not  stop  abruptly  and  then  reappear,  but 
pass  gradually  from  the  edge  to  the  center.  In  the 
early  stage  of  atrophy,  the  arteries  are  small  and  the 
veins  are  full,  but  in  the  late  stage  of  atrophy  (com- 
plete) both  arteries  and  veins  are  very  much  dimin- 
ished in  calibre  and  cannot  be  readily  distinguished 
from  each  other  by  the  light  streak,  as  in  the  normal 
eye.  The  color  of  the  disc  in  this  last  stage  of 
atrophy  is  white  or  chalky,  sometimes  spoken  of  as 
bluish-white,  or  the  color  of  skimmed  milk.  This 
color  extends  to  the  edge  of  the  disc.  Plate  X. 
shows  the  white  disc,  and  Fig.  73,  No.  2,  a  section 
illustrating  the  gradual  saucer  curve,  or  bow  shape, 
to  the  disc. 

To  summarize: 

Physiologic  Cupping  Glaucoma  Cupping 

(Fig.  73,  No.  i).  (Fig.  73,  No.  3)- 

I.  Cupping  is  central  or  to  tern-       I.  Cupping  entire, 
poral    side.     Shelving   from 
the  side. 


ELEVATION    OF    DISC.  235 

Physiological  Cupping.  Glaucoma  Cupping. 

2.  Cupping  gradual  or  abrupt.  2.  Cupping  has   abrupt   edges. 

3.  Vessels  normal.  3.  Veins  full,  arteries  small. 

4.  Parallax  occasionally  marked.  4.  Parallax  very  marked. 

5.  Normal  color  of  disc.  5.  Gray  or  pearly  white  color  of 

disc. 

A  trap  hie 
(Fig.  73,  No.  2). 

1.  Depression  is  entire. 

2.  Gradual  sloping. 

3.  Arteries  and  veins  indistinguishable. 

4.  No  parallax. 

5.  Disc  white  in  color. 

Elevation  of  Disc,  the  Swollen  Disc.  This  is 
the  very  reverse  of  the  three  conditions  just  de- 
scribed. This  is  spoken  of  as  optic  neuritis,  papil- 
litis,  choked  disc.  Remembering  the  anatomy  of 
the  parts,  how  the  sheath  of  the  optic  nerve  is  con- 
tinuous with  the  sclerotic  coat,  and  between  the 
nerve  and  its  sheath  is  the  arachnoid  space,  how  the 
fibers  of  the  nerve  with  artery  or  arteries  and  veins 
passed  through  the  membrana  cribrosa,  then  any 
portion  of  the  nerve  lying  in  front  of  the  mem- 
brana cribrosa,  must  become  constricted  by  this 
membrana  cribrosa  during  inflammation  of  the 
nerve  fibers,  and  this  therefore  means  a  compres- 
sion or  squeezing  of  the  disc,  and  hence  its  name 
"choked  disc,"  papillitis,  or  optic  neuritis.  If  the 
disc  swells,  it  must  project  forward  into  the  vitreous 
and  also  laterally.  The  swelling  of  the  disc,  whether 
due  to  pressure  on  the  nerve  fibers  while  in  the 
nerve  sheath  before  entering  the  scleral  openings, 
or  from  obstruction  to  venous  or  arterial  blood,  or 


236  THE   OPHTHALMOSCOPE. 

by  infection  or  proliferation;  no  matter  what  the 
cause,  the  condition  is  the  same  in  all,  viz.,  swelling. 
The  presence  of  the  swollen  or  elevated  nerve  head 
can  be  proven  by  the  different  strength  lens  re- 
quired in  the  ophthalmoscope  to  see  first  the  top  of 
the  disc  and  then  the  edge  of  the  disc  or  the  sur- 
rounding eye  ground.  The  swollen  nerve  head  is 
composed  of  nerve  fibers,  inflammatory  products, 
contracted  arteries  and  very  full  veins.  The  di- 
ameter of  the  nerve  head  must  therefore  be  much 
greater  than  normal;  three  times  its  normal  diam- 
eter has  been  reported.  The  nerve  fibers,  as  they 
pass  from  the  disc,  are  seen  to  be  swollen  for  some 
distance  beyond  its  normal  edge.  They  are  opaque 
and  gray  in  color.  The  edge  of  the  disc  is  no  longer 
clear  cut  but  rather  indefinite  and  merges  gradu- 
ally into  the  surrounding  fundus.  The  margin  of 
the  disc  is  spoken  of  as  foggy,  misty  or  woolly. 
The  veins  are  full  and  tortuous,  as  the  return  blood 
from  the  retina  cannot  get  out  of  the  eye  on  account 
of  the  swelling.  The  arteries  on  the  disc  and  in 
the  retina  are  smaller  for  the  same  reason  that  the 
veins  cannot  carry  the  blood  from  the  eye,  so  the 
arterial  blood  cannot  get  into  the  eye.  The  veins 
are  more  or  less  covered  by  inflammatory  products 
and  in  some  places  they  may  be  completely  covered, 
or  here  and  there  come  into  view  but  are  rarely 
seen  distinctly.  The  arteries  are  often  so  small  in 
caliber  as  to  appear  like  threads  and  are  seen  with 
difficulty,  or  possibly  cannot  be  seen  at  all.  The 


CONSTRICTION    OF    CIRCULATION. 

swollen  nerve  head  may  be  described  or  considered 
in  three  stages,  the  stage  of  swelling  or  constriction 
of  the  circulation ;  stage  of  effusion ;  stage  of  reso- 
lution, or  absorption  and  atrophy. 

Stage  of  Swelling  or  Constriction  of  the  Cir- 
culation. The  elevation  or  swelling,  while  it  may 
be,  and  often  is,  irregular,  slopes  gradually  down- 
ward from  the  center  into  the  surrounding  eye 
ground  and  the  blood  vessels  follow  the  same  slopes. 
The  nerve  fibers  are  swollen  and  more  or  less 
opaque  and  give  the  nerve  head  a  striated  appear- 
ance. The  disc  margin,  if  it  can  be  seen,  is  very 
indistinct  or  foggy,  not  definite  or  clear  cut.  The 
color  of  the  disc  is  variously  described  as  "  red- 
dish-gray," "  brick  dust  red,"  and  even  as  violet 
and  bluish.  The  veins  are  dark  or  almost  black  in 
color,  full  and  tortuous.  The  arteries  are  small 
and  do  not  carry  much  blood.  This  is  the  first 
stage  of  optic  neuritis,  or  choked  disc,  or  papillitis. 
The  height  of  the  swelling  is  calculated  by  the 
strength  of  lens  in  the  ophthalmoscope  required  to 
see  the  top  or  apex  of  the  swelling,  as  compared 
with  the  strength  of  lens  required  to  see  the  sur- 
rounding eye  ground,  each  three  diopters  represent- 
ing very  closely  one  millimeter  of  elevation. 

Stage  of  Effusion  or  Cell  Proliferation.  The 
swelling  of  the  disc  is  now  quite  regular,  and  the 
striation  is  not  nearly  so  well  marked.  The  effusion 
or  exudation  extends  well  beyond  the  disc  margin, 
giving  a  decided  opaque  appearance  which  blurs 


238  THE   OPHTHALMOSCOPE. 

or  obscures  all  fine  detail  observations.  The  central 
vessels  are  more  or  less  concealed  by  the  effusion 
and  the  arteries  may  not  be  seen.  The  color  of 
the  disc  is  not  now  as  red  as  in  the  first  stage,  but 
is  a  dirty  gray,  and  hemorrhages  of  varying  sizes 
and  shapes  may  be  seen  on  and  around  the  disc,  and 
through  the  eye  ground. 

The  Stage  of  Resolution  or  Absorption  and 
Atrophy.  As  the  inflammation  gradually  subsides 
the  swelling  diminishes  and  the  effusion  is  very 
slowly  absorbed.  The  veins  become  less  tortuous 
and  their  color  less  dark.  They  also  diminish  in 
caliber.  The  arteries  remain  thread-like  and  some 
of  them  may  not  be  seen  at  all.  The  color  of  the 
disc  is  entirely  white,  or  the  color  of  chalk,  and 
may  appear  glistening.  This  is  the  declining  or 
final  stage  of  optic  neuritis.  The  surrounding  eye 
ground  shows  faint  and  irregular  pigmentation; 
this  is  often  quite  marked  at  the  edge  of  the  disc 
(Plate  IX.). 

Optic  Neuritis.  There  are  several  varieties  of 
neuritis  named  principally,  from  the  anatomic  parts 
or  part  of  the  nerve  involved. 

Papillitis.  Inflammation  of  that  portion  of  the 
nerve  which  is  anterior  to  the  membrana  cribrosa, 
or  an  inflammation  of  that  portion  of  the  nerve 
which  can  be  seen  with  the  ophthalmoscope. 

Papillo-retinitis.  Papillitis  associated  with 
retinitis. 

Ascending  Neuritis.     This  is  an  inflammation 


PAPILLITIS.  239 

which  starts  at  the  eye  and  extends  or  ascends 
toward  the  brain.  Descending  Neuritis  is  the  re- 
verse of  the  ascending  variety,  the  inflammation 
starting  in  the  brain  or  back  of  the  eye  and  de- 
scending toward  the  eye.  An  inflammation  of  the 
nerve  back  of  the  eye,  is  spoken  of  as  retro-bulbar 
.neuritis.  A  partial  neuritis  is  an  inflammation  of 
a  part  and  not  the  whole  of  the  nerve. 

Papillitis,  also  called  Choked  Disc,  Neuritis, 
Intra-ocular  Optic  Neuritis.  This  begins  as  a 
hyperemia  of  the  disc  and  passes  into  a  stage  of 
swelling  so  that  the  disc  projects  into  the  vitreous 
and  its  apex  is  seen  with  a  different  strength  lens 
than  is  required  to  see  the  surrounding  eye  ground. 
According  to  Untoff,  the  elevation  of  the  disc 
should  be  about  two-thirds  of  one  millimeter  before 
it  is  spoken  of  as  choked  disc.  The  disc  is  also  seen 
to  be  two  or  three  times  its  normal  width.  The 
physiologic  cupping,  if  previously  present,  is  now 
absent.  Hemorrhages,  few  or  many,  may  be  seen 
in  and  about  the  disc  and  occasionally  throughout 
the  fundus.  The  arteries  and  veins  are  seen  to 
pass  down  from  the  apex  or  summit  of  the  swollen 
disc  and  to  bend  abruptly  to  the  level  of  the  sur- 
rounding eye  ground.  The  arteries  are  so  crowded 
or  pressed  upon  that  the  blood  cannot  pass  through 
into  the  eye,  and  naturally  they  maintain  more  or 
less  of  their  straight  course,  and  on  account  of  the 
same  pressure  the  veins  become  full,  swollen  and 
tortuous  because  the  blood  cannot  get  out  of  the 


240  THE    OPHTHALMOSCOPE. 

eye  and  must  remain  backed  up  in  the  veins.  The 
veins  get  so  full  and  tortuous  as  to  appear  like  half 
circles  (-Plate  III.)  or  serpentine,  and  hence  the 
name  of  "medusa  nerve,"  given  to  the  veins  and 
disc. 

Papillitis  usually  appears  in  both  eyes,  but  may 
occur  in  one  and  when  seen  in  one  eye  alone  it  may 
be  due  to  a  local  cause  in  the  same  orbit,  and  this 
should  be  carefully  looked  for.  If  the  cause  is  not 
local  then  tumor  of  the  brain  may  be  diagnosed 
with  considerable  certainty,  and  as  being  on  the 
side  of  the  brain  corresponding  to  the  eye  affected. 
Papillitis,  while  so  suggestive  of  brain  tumor,  does 
not  indicate  the  portion  of  the  brain  implicated. 

Vision  and  Visual  Field.  In  papillitis  the  cen- 
tral vision  may  be  normal  at  first,  but  later  on  may 
become  affected  (see  footnote,  page  18).  In 
rare  instances  central  vision  may  be  lost  sud- 
denly. The  field  of  vision  is  irregular  in  the 
periphery  and  the  blind  spot  is  enlarged.  Color 
vision  may  be  affected  and  hemianopsia  may  be 
present,  under  certain  conditions. 

Course  of  Papillitis.  As  the  retina  is  in  great 
part  a  continuation  of  the  optic  nerve,  it  is  difficult 
to  imagine  a  case  of  papillitis  without  some  involve- 
ment of  the  retina,  and  it  becomes  quite  doubtful 
if  papillitis  can  exist  "  per  se."  In  cases  of  choked 
disc  that  recover  the  inflammation  gradually  sub- 
sides and  atrophy  supervenes.  The  swelling  dimin- 
ishes in  the  disc  and  retina,  the  hemorrhages  are 


CAUSES   OF    PAPILLITIS.  24! 

absorbed  without  leaving  any  trace  of  their  pres- 
ence, unless  quite  large,  when  they  occasionally 
leave  yellowish-white  patches  in  the  retina  which 
mark  their  previous  existence.  For  a  time  the 
veins  and  arteries  may  regain  in  great  part  their 
normal  positions  and  size,  and  may  remain  so  if  ex- 
tensive atrophy  does  not  follow.  The  disc  may  ap- 
proximate the  normal  state  also,  but  with  irregular 
edges  and  with  scattered  broken  pigment  massings. 
This  is  an  important  part  of  the  differential  diagno- 
sis between  atrophy  following  choked  disc  (Plate 
IX.)  and  atrophy  following  medullary  or  interstitial 
neuritis  (Plate  X.)  where  the  disc  edges  are  clean 
cut  and  well  defined.  Vision  is  usually  very  much 
reduced  and  peripheral  vision  irregularly  con- 
tracted. 

Causes  of  Papillitis.  Of  all  the  causes  of  papil- 
litis  by  far  the  most  common  is  tumor  of  the  brain, 
namely,  gumma,  sarcoma,  fibroma,  carcinoma,  etc. ; 
or  to  state  the  fact  more  definitely,  no  matter  what 
the  size  of  the  tumor  in  the  brain  may  be,  large  or 
small,  or  its  variety  or  its  location  in  the  brain, 
78  per  cent,  of  cases  of  brain  tumor  develop  papil- 
litis  as  the  most  important  symptom.  The  follow- 
ing very  interesting  and  instructive  table  "The 
Papillitis  Accompanying  Brain  Tumor,"  by  John 
E.  Weeks,  M.D.,  presented  at  the  Section  on  Oph- 
thalmology at  the  fiftieth  annual  meeting  of  the 
American  Medical  Association  held  at  Columbus, 
Ohio,  June  6  to  9,  1899,  gives  the  percentages  of 


242 


THE   OPHTHALMOSCOPE. 


choked  discs,  resulting  from  tumor  in  the  brain 
and  the  locations  of  the  tumors,  etc. 


Location. 

6 
K 

~  « 

o:| 
cz 

** 

Unilateral. 

Double 
Optic 
Neuritis. 

Per  Cent. 

Frontal  lobes  

64 

12 

4 

48 

80.7 

Temporo-sphenoidal  

24 

9 

O 

1C 

62.5 

Motor  area  

m 

46 

7 

64 

SQ.  2 

Parieto-occipital  

77 

4 

7 

26 

87.8 

Brain  surface  

17 

4 

O 

60.2 

Centrum  ovale  

58 

17 

2 

TO 

70.7 

Corpora  quadrigemina  

10 

o 

o 

IQ 

IOO 

Basal  ganglia  

36 

1C 

O 

22 

61.1 

Multiple  

•jq 

II 

2 

26 

46.6 

Corpus  callosum  

12 

7 

O 

41.7 

Pituitary  body  

18 

O 

SO 

Pineal  gland  

i 

I 

o 

o 

O 

Crura  

c 

I 

o 

4 

80 

Pons  

So 

20 

c 

2? 

60 

Cerebellum  

164 

21 

170 

87.2 

Base  of  cranium  

IO 

I 

o 

oo 

IO 

II 

8^.7 

Totals  

677 

1  80 

27 

470 

69.4 

Among  other  causes  of  choked  disc  or  papillitis 
may  be  mentioned  meningitis  in  any  of  its  varieties, 
especially  the  tubercular,  occurring  among  children 
as  a  rather  frequent  cause.  The  following  have 
been  noted  as  causing  papillitis,  albuminuria,  dia- 
betes, rheumatism,  brain  abscess,  hydrocephalus, 
thrombosis  of  the  cavernous  sinus,  acromegaly 
(swollen  pituitary  body),  aneurism,  cysts,  hemor- 
rhage of  the  meninges  and  traumas.  Papillitis  has 
been  noted  during  typhoid  fever,  scarlet  fever,  diph- 
theria, small-pox,  erysipelas,  syphilis,  influenza,  etc. 
Sunstroke,  disturbances  of  menstruation,  lead  and 


TREATMENT    OF    PAPILLITIS.  243 

alcohol  have  also  been  recorded  as  causes,  showing 
that  the  causes  of  papillitis  are  very  many  and  vari- 
ous, and  yet  cases  occur  idiopathically. 

Prognosis.  No  matter  what  the  cause  of  the 
papillitis,  the  prognosis  must  always  be  grave,  for 
the  simple  reason  that  the  vision  is  always  more  or 
less  damaged,  the  one  exception  to  this  statement 
being  the  toxic  amblyopias,  which  may  recover, 
otherwise  the  underlying  cause  of  the  papillitis 
(tumor  of  the  brain,  etc.)  places  the  patient's  life 
in  danger. 

Treatment.  The  cause  must  be  carefully  sought 
for  and  carefully  treated.  Patients  having  pap- 
illitis due  to  syphilis  must  be  brought  promptly 
under  the  influence  of  mercury  and  as  soon  as 
this  is  accomplished  iodids  should  be  pushed 
to  iodism.  Menstrual  disorders  should  be  cor- 
rected when  they  are  the  underlying  cause. 
The  alterative  action  of  mercury  and  the  iodids 
is  appropriate  treatment  in  almost  every  in- 
stance, with  the  exception  of  the  tubercular. 
When  the  papillitis  is  due  to  a  growth  the  case 
should  have  the  opinion  of  a  neurologist  and 
surgeon. 

Neuro-retinitis,  or  Papillo-retinitis  (Plate  V.). 
With  swelling  of  the  disc  as  described  under  Papil- 
litis, the  retina  usually  becomes  involved  and  as  this 
membrane  becomes  swollen  and  opaque  the  retinal 
vessels  become  more  or  less  hidden  in  the  swelling 
and  resulting  exudates.  Hemorrhages  make  their 


244  THE    OPHTHALMOSCOPE. 

appearance  in  the  course  of  the  vessels  and  have 
flame-shaped  edges  as  they  lie  in  the  nerve  fiber 
layer.  Large  and  scattered  areas  of  exudate  make 
their  appearance,  and  also  an  irregular  star-shaped 
figure  at  the  macula,  not  unlike  the  condition  seen 
in  albuminuric  retinitis. 

The  differential  diagnosis  between  papillitis  per  se 
or  neuro-retinitis  due  to  brain  tumor  and  albumin- 
uric  retinitis  is  not  always  easy,  and  must  be  very 
carefully  studied  before  coming  to  a  positive  diag- 
nosis. The  addition  of  palsies  of  any  of  the  ocular 
muscles  would  strongly  suggest  a  growth  in  the 
brain  while  the  absence  of  palsies  and  the  presence 
of  albumen  and  casts  in  the  urine  would  indicate 
nephritis,  though  both  conditions  have  been  known 
to  exist  in  the  same  patient. 

Retrobulbar  Neuritis — Acute  and  Chronic, 
Medullary  Neuritis,  Interstitial  Neuritis.  This  is 
an  inflammation  of  the  optic  nerve  back  of  the  eye- 
ball and  within  the  orbit,  therefore  anterior  to  the 
optic  foramen. 

Acute  Retrobulbar  Neuritis.  Early  in  the  dis- 
ease there  are  few  ophthalmoscopic  changes  noted, 
and  when  they  do  appear  they  are  slight  and  may 
be  overlooked,  viz.,  hyperemia  of  the  disc  with  its 
edges  hazy.  The  diagnosis  is  made  primarily  from 
rapidly  failing  vision  (central)  \vhich  brings  the 
patient  under  observation;  in  such  instances  this 
failure  of  vision  may  result  in  almost  complete 
blindness  in  a  few  days. 


CHRONIC    RETROBUL13AR    NEURITIS.  245 

Causes.  Syphilis  (gumma) ;  taking  cold;  rheu- 
matism; methyl  alcohol;  quinin;  autotoxemia;  dis- 
turbed menstruation ;  diabetes ;  periostitis ;  injuries. 
In  some  instances  no  cause  can  be  found.  In  other 
cases  it  may  be  caused  by  decayed  teeth,  growths, 
pressure,  ethmoiditis,  etc. 

Prognosis.  This  must  be  very  guarded,  though 
many  cases  recover;  yet  some  few  do  not.  For- 
tunately it  is  often  a  unilateral  disease. 

Treatment.    This  is  the  treatment  of  the  cause. 

Chronic  Retrobulbar  Neuritis,  Tobacco  Am- 
blyopia,  Toxic  Amblyopia.  Patients  complain 
of  poor  vision  for  near  work  which  cannot  be 
materially  improved  with  any  glass,  and  state 
that  vision  is  apparently  better  on  a  dull  or 
cloudy  day  and  is  worse  when  the  sun  shines 
brightly.  The  ophthalmoscope  reveals  almost  a 
normal  fundus,  unless  the  case  is  well  advanced, 
when  the  disc  may  appear  pale  in  whole  or  in  part. 

The  field  chart  may  be  quite  normal  for  form, 
but  central  scotoma  for  red  and  green  is  present; 
this  scotoma  is  usually  the  same  in  both  eyes,  hori- 
zontally oval  and  extends  from  and  including  the 
normal  blind  spot  to  the  macula,  showing  the  in- 
fluence of  the  disease  on  what  is  known  as  the  pap- 
illomacular  fibers,  the  nerve  fibers  passing  from  the 
disc  to  the  macula. 

Causes.  As  its  name  implies  (tobacco  ambly- 
opia,  blunted  sight  from  tobacco)  this  chronic 
retrobulbar  neuritis  is  frequently  caused  by  over- 


246  THE   OPHTHALMOSCOPE. 

use  of  tobacco  and  very  often  this  habit  is  associ- 
ated with  some  moderate  or  excessive  use  of  alcohol 
in  some  form.  The  writer  might  state  that  there 
is  no  rule  or  guide  as  to  just  how  much  smoking  or 
drinking  will  produce  toxic  amblyopia — "  What  is 
food  for  one  is  poison  for  another."  Some  men 
can  drink  and  smoke  excessively  and  never  develop 
amblyopia,  whereas  another  may  develop  ambly- 
opia from  only  a  moderate  use  of  these  toxic  agents. 
Tobacco  amblyopia  seldom  develops  before  the  age 
of  forty.  Other  substances  that  will  produce  the 
same  symptoms  are  essence  of  ginger,  strong  coffee 
to  excess,  chloroform,  opium,  chloral,  arsenic,  iodo- 
form,  quinin,  salicylic  acid,  acetanilid,  caffein,  bi- 
sulphid  of  carbon,  nitro-benzol,  methyl  alcohol 
(wood  alcohol),  etc. 

Prognosis.  Favorable  if  due  to  alcohol  and  to- 
bacco and  the  patient  comes  under  observation  early 
and  carries  out  the  treatment.  The  prognosis  must 
be  guarded  in  any  instance  and  when  due  to  causes 
other  than  tobacco  and  alcohol  the  history  of  the 
patient  must  have  careful  consideration. 

Treatment.  Stop  the  cause  if  possible.  Pilo- 
carpin  sweats  occasionally;  strychnia  in  tonic  doses 
and  the  use  of  iodid  of  potash  as  an  absorbent. 
The  patient  must  also  be  cautioned  against  return- 
ing to  the  use  of  the  drug  or  any  drug  which  might 
bring  back  a  recurrence  of  the  nerve  condition. 

Optic  Nerve  Atrophy.  There  is  no  portion  of 
the  optic  nerve  exempt  from  this  condition  of 


PLATE  IX. 

ATROPHY  OF  THE  OPTIC  NERVE  (Posr  PAPILLITIC  ATROPHY).    ALSO 

MEDULLARY   NERVE-FIBERS.    FUNDUS   OF  RIGHT   EYE. 

DIRECT  METHOD. 

Miss  L.  D.     Aged  16  years. 

History.  Patient  was  treated  for  "  Choked  Disc "  in  1901.  Had 
a  tumor  (gumma  (  ?)  )  of  the  brain.  Patient  treated  by  Drs.  Mus- 
ser,  Spiller  and  Hermance. 

Fundus  Changes.  Disc  is  bluish  in  color.  The  edges  are  not 
well  defined.  Lamina  cribrosa  is  not  present.  As  a  coincidence 
there  are  medullary  nerve-fibers  present  at  the  upper  edge  of  the 
disc.  The  whole  fundus  is  peculiarly  mottled  (map-like).  The 
retina  is  atrophied  and  the  macula  cannot  be  distinguished.  Arte- 
ries are  straight  and  some  of  the  larger  veins  slightly  tortuous. 
Left  eye  similarly  affected,  but  without  the  medullary  fibers  and  not 
such  an  extensive  atrophy. 

March  31,  1905.  Vision  of  right  eye  with  -f-  i.oo  Cyl.  axis  100 
degrees  =  light  perception. 

Vision  of  left  eye  with  -f-  i.oo  Cyl.  axis  80  degrees  =  VI/X. 


248 


PLATE    IX 


Atrophy  of  the  Optic  Nerve 

(Past  Papillitic  Atrophy) 
Also.  Medullated  Nerve-fibers 


PLATE   X. 

PRIMARY  OPTIC  ATROPHY.     (SPINAL  ATROPHY.)     FUNDUS  OF  RIGHT 

EYE.     DIRECT  METHOD.    FUNDUS  OF  LEFT  EYE 

ABOUT  THE  SAME. 

Mr.  William  S.  S.    Aged  54  years.     Dyer  by  occupation. 

History.  Vision  has  been  failing  gradually  for  two  years.  Has 
been  using  various  glasses  to  read  with  and  now  cannot  read  with  any 
glasses  that  he  can  purchase.  His  walk  has  been  impaired  for  about 
the  same  length  of  time  that  his  sight  has  been  failing  him.  His- 
tory of  syphilis.  Uses  tobacco  and  alcohol  to  excess. 

Irises  do  not  react  to  light  stimulus,  but  do  respond  to  conver- 
gence and  accommodation  (Argyll-Robertson  Pupils). 

Fundus  Changes.  Vision  of  each  eye  about  i/io.  Disc  bluish  in 
color  and  glistening.  Membrana  cribrosa  is  seen  at  the  center  of 
the  disc.  The  disc  has  a  white  edge,  called  by  some  a  scleral  ring. 
A  cilio-retinal  vessel  is  seen  on  the  temporal  edge  of  disc  passing 
toward  the  macula.  Fundus  reflex  apparently  normal.  Vessels  arc 
not  particularly  narrowed  at  the  present  time.  Arteriosclerosis  evi- 
dent at  crossing  of  vessels.  Disc  has  "  saucer "  shaped  excavation. 


252 


PLATE   X 


Primary  Optic  Atrophy 


PRIMARY   ATROPHY.  255 

shrinking  of  its  elements  from  the  brain  center  up 
to  and  including  the  papilla.  There  are  three  dis- 
tinct forms  of  atrophy,  primary,  secondary  and 
consecutive. 

Primary  Atrophy.  Spoken  of  as  progressive, 
degenerative,  gray,  spinal  or  tabetic  atrophy  (Plate 
X.).  This  is  an  atrophy  that  appears  without  any 
apparent  or  very  slight  previous  inflammation.  It 
is  usually  bilateral.  It  may  be  a  local  condition  of 
one  eye,  but  it  is  usually  met  with  in  locomotor 
ataxia  and  disseminated  sclerosis,  therefore  affect- 
ing both  eyes.  Spinal  disease  (33  per  cent.)  is 
the  most  common  cause  of  gray  degeneration  of  the 
optic  nerve,  especially  in  locomotor  ataxia.  Among 
other  causes  are,  malnutrition,  taking  cold,  dis- 
turbed menstruation,  syphilis,  drugs,  etc. ;  and  occa- 
sionally the  cause  may  be  unknown.  Hereditary 
predisposition;  this  latter  variety,  if  it  may  be  so 
called,  has  been  known  to  appear  in  the  male  mem- 
bers of  a  family  generation  after  generation,  and 
to  develop  about  the  age  of  twenty-one  years. 

Secondary  Atrophy.  This  means  that  the  nerve 
has  degenerated  by  reason  of  some  previous  lesion, 
such  as  fracture  of  the  optic  foramen,  pressure  on 
the  optic  tract,  etc.,  or  a  disease  of  the  nerve  or 
retina,  embolism  of  the  central  artery  of  the  retina, 
retinitis  pigmentosa,  retino-choroiditis,  syphilitic 
retinitis,  glaucoma,  etc. 

Consecutive  Atrophy.  Also  spoken  of  as  post- 
neuritic  atrophy  or  post-papillitic  atrophy.  This  is 


256  THE   OPHTHALMOSCOPE. 

the  variety  of  wasting  that  follows  an  inflammation 
like  papillitis  (Plate  IX.).  The  terms  secondary 
and  consecutive  atrophy  are  often  confused. 

Ophthalmoscopic  Appearances.  To  study  the 
different  varieties  of  atrophy,  it  is  well  to  employ 
both  the  direct  and  the  indirect  methods.  The  two 
principal  characteristics  of  atrophy  as  seen  with 
the  ophthalmoscope  are  paleness  or  whiteness 
of  the  disc  and  a  diminution  in  the  vascularity. 
The  disc  (principally  the  intermediate  zone) 
loses  its  normal  pink  or  yellowish  red  color  and 
appears  pale.  It  is  the  capillary  circulation  that 
produces  the  shell  pink  color  of  the  normal  healthy 
disc,  and  when  this  circulation  is  destroyed  atrophy 
must  be  present.  It  is  not  absolutely  necessary  to 
have  the  large  vessels  of  the  disc  diminished  in 
size  to  have  atrophy,  and  sometimes  the  large  ves- 
sels do  not  perceptibly  diminish  in  size  until  late  in 
the  disease.  It  may  also  be  stated  that  occasionally 
the  large  vessels  may  diminish  in  size  and  atrophy 
develop  before  the  capillary  circulation  disappears 
or  lessens.  The  color  of  the  disc  in  atrophy  is  not 
the  same  in  all  eyes,  and  has  been  described  as 
white,  chalky  white,  snow  white,  cottony  white, 
pearly  white,  gray,  grayish-white,  bluish,  skim  milk, 
green,  etc.  These  colorings  are  controlled  in  great 
degree  by  (a)  the  reflected  light,  its  quality,  color 
and  intensity;  (b)  by  the  comparative  color  of  the 
surrounding  eye  ground;  (c)  by  the  presence  or 
absence  of  the  physiologic  or  glaucoma  cupping; 


OPHTHALMOSCOPIC   APPEARANCES.  257 

(d)  by  the  membrana  cribrosa,  if  present  or  ab- 
sent; and  also  (e)  by  the  character  of  the  inflam- 
mation previous  to  the  atrophy.  The  colorings  of 
the  nerve  in  atrophy  cannot  be  attributed  to  pig- 
mentation. Of  course  the  observer's  idea  of  color 
must  also  enter  into  the  description  of  the  color  of 
the  atrophic  disc.  The  color  of  the  atrophic  disc  is 
not  always  uniform;  the  center  may  be  stippled 
white  and  gray,  and  the  edge  have  a  gray  or  green- 
ish or  bluish  tinge  (Plate  X.),  and  so  there  are  in- 
numerable variations. 

Causes.  Most  cases  of  locomotor  ataxia  are  ac- 
companied sooner  or  later  by  primary  optic  atrophy 
and  in  fact  optic  atrophy  may  be  a  preataxic  symp- 
tom. Multiple  sclerosis  is  another  cause  of  pri- 
mary optic  atrophy,  as  also  epilepsy  and  progressive 
paralysis  (see  page  255). 

Differential  Diagnosis.  Atrophy  following 
papillitis  and  primary  atrophy  are  not  the  same  in 
all  particulars,  though  they  have  many  points  of 
similarity. 

Primary  Atrophy  Atrophy  from  Papillitis 

(Plate  X.).  (Plate  IX.). 

Disc  very  brilliant  and  glistening  White    color   of   disc,   not   bril- 

white — pearly  white,  or  gray.  liant;    appears    a    dirty    gray, 

described  as  bluish. 

Disc  edges  sharply  cut.  Disc  edges  not  usually  well  de- 
fined. 

Lamina  cribrosa  very  conspicu-  Lamina  cribrosa  usually  not  con- 

ous.  spicuous. 

Arteries   and  veins  not  so  con-  Arteries  and  veins  very  narrow ; 

tracted.  veins  tortuous. 
Excavation,  if  present,  is  saucer 
shaped. 


258  THE   OPHTHALMOSCOPE. 

Diagnosis  of  Optic  Atrophy.  The  ophthalmo- 
scopic  findings  make  the  diagnosis  quite  easy  when 
the  disease  is  well  advanced,  but  if  the  disc  has  not 
become  decidedly  pale,  then  other  symptoms  must 
have  careful  consideration.  The  central  vision  may 
remain  good  for  quite  a  while  whereas  peripheral 
vision  may  be  concentrically  contracted,  the  color 
fields  contracted  and  central  scotoma  evident.  The 
history  of  the  patient  is  also  of  considerable  im- 
portance. 

Prognosis.  Unfavorable.  The  condition  leads 
to  blindness  in  most  instances.  Of  course  the  prog- 
nosis must  be  controlled  by  the  underlying  cause. 
Syphilitic  cases  appearing  early  give  a  fair  prog- 
nosis. In  cases  of  locomotor  ataxia,  the  atrophy 
advances  and  blindness  eventually  takes  place. 

Treatment.  This  depends  upon  the  cause.  If 
syphilis  is  suspected  then  mercury  and  iodids  should 
be  prescribed  and  pushed  to  the  point  of  tolerance. 
When  due  to  other  causes,  nerve  stimulants, 
strychnia  by  mouth  and  hypodermically,  nitro- 
glycerin,  phosphorus,  iron,  etc.,  may  be  prescribed 
as  indicated  and  galvanism  may  be  tried. 


CHAPTER   X. 

DISEASES   OF  THE  CHOROID.     GLAUCOMA. 

DISEASES  of  the  choroid,  like  diseases  of  the 
retina  and  optic  nerve,  give  defective  vision  as  the 
most  important  symptom  to  the  patient,  without  any 
external  manifestations  of  the  inward  changes.  It 
is  unfortunate  for  the  patient  that  these  structures 
are  not  supplied  with  nerves  of  painful  sensation 
like  the  iris  and  ciliary  body,  so  that  the  patient 
would  come  under  observation  much  sooner  and 
before  serious  damage  to  vision  has  resulted.  Dis- 
eases of  the  choroidal  coat  of  the  eye  are  indicated 
with  the  ophthalmoscope  by  many  changes  from  the 
normal  appearance  of  this  tunic,  namely: 

1.  Changes  in  the  color  of  the  eye  ground. 

2.  Inflammatory  products,  patches  of  exudation, 
and  changes  in  elevation. 

3.  Changes  in  pigmentation. 

4.  Areas  or  white  patches  of  exposed  sclerotic 
resulting  from  absorption  of  choroid  and  retinal 
tissue. 

Changes  in  Color.  A  diagnosis  of  hyperemia 
of  the  choroid  or  disturbed  choroid  is  not  easily 
made  by  the  beginner  in  ophthalmoscopy,  and  it  is 
not  until  an  infiltration  has  taken  place  which  gives 
the  previously  red  reflex  a  yellowish  tinge,  that  the 

259 


26O  THE    OPHTHALMOSCOPE. 

inflammation  of  the  choroid  is  definitely  recognized. 
Fortunately,  from  a  diagnostic  point  of  view,  in- 
flammation of  the  choroid  does  not  occur  in  the 
whole  choroid  at  one  and  the  same  time,  but  is  seen 
in  scattered  areas. 

Inflammatory  Products.  Areas  of  exudation 
may  appear  round  or  oval  or  irregular  in  form, 
but  they  are  usually  oval  in  outline.  These  spots  or 
areas  being  pale  yellow  in  color,  are  to  be  distin- 
guished from  an  opaque  or  foggy  retina.  Patches 
of  recent  choroiditis,  while  elevated  are  at  a  greater 
depth,  and  at  some  few,  or  many  points  retinal 
vessels  may  be  seen  passing  over  them,  and  they 
are  therefore  elevated  on  these  patches.  Opacities 
are  sometimes  seen  floating  in  the  vitreous,  appear- 
ing like  dust  particles,  or  threads. 

Changes  in  Pigmentation.  Another  decided 
characteristic  of  inflammation  in  the  choroid  is 
the  change  in  its  pigmentation  at  and  around  the 
spot  of  inflammation,  and  the  retinal  vessels  are 
often  seen  passing  over  these  inflamed  areas 
which  of  course  include  the  pigmentation  if 
the  disease  is  advanced.  The  pigmentation  is 
never  uniform,  but  is  usually  quite  irregular, 
sometimes  rounded,  sometimes  crescentic;  it  is 
brown  or  black  in  color  giving  the  fundus  the  ap- 
pearance of  having  had  blots  of  ink  scattered  over 
it.  The  number  and  character  of  these  black  spots 
is  usually  in  keeping  with  the  number  and  size 
of  the  areas  of  inflammation.  Pigmentation  is  usu- 


ATROPHY.  26l 

ally  a  late  manifestation  of  an  area  of  choroiditis. 
Areas  of  choroiditis  may  be  seen  in  various  stages 
of  inflammation  in  the  same  eye  ground.  New 
areas  appear  while  others  have  reached  the  atrophic 
stage. 

Atrophy.  This  condition  of  the  choroid  natur- 
ally follows  absorption  of  the  exudates  at  the  areas 
of  inflammation,  and  is  indicated  by  white  areas 
of  irregular  shape  with  scattered  pigment  at  the 
edges.  Spots  of  atrophy  (exposed  sclera)  stand 
out  in  bold  relief.  It  is  not  unusual  to  see  a  few 
choroidal  vessels  passing  through  atrophic  areas. 

Hemorrhage  of  the  Choroid,  while  it  may  take 
place,  and  no  doubt  often  does  occur  (when  the 
extensive  vascularity  of  the  choroid  is  taken  into 
consideration),  yet  hemorrhage  of  the  choroid  is 
not  easily  recognized  with  the  ophthalmoscope,  as 
the  retinal  layers  hide  them  unless  they  are  large 
and  very  extensive,  when  they  may  break  through 
into  the  deep  layers  of  the  retina,  or  even  into  the 
vitreous. 

Inflammation  of  the  Choroid  (choroiditis)  is 
a  very  indefinite  name  unless  qualified,  so  as  to  give 
the  variety  and  if  possible  the  cause  of  the  inflam- 
mation. Furthermore,  choroiditis  has  come  to 
mean  not  only  an  active  inflammatory  state,  but  a 
condition  of  the  choroid  after  the  inflammation  has 
subsided.  Choroiditis  is  said  to  be  the  most  com- 
mon of  fundus  diseases  and  only  too  frequently 
it  damages  or  destroys  the  sight. 


262  THE    OPHTHALMOSCOPE. 

The  varieties  of  choroiditis  are  innumerable,  and 
have  been  variously  classed,  but  each  variety  pre- 
sents one  or  more  of  the  characteristics  just  de- 
scribed. Superficial  and  deep  choroiditis  are  so 
called  on  account  of  the  part  of  the  choroid  af- 
fected. The  terms  acute  and  chronic  are  self- 
explanatory,  and  disseminated  means  that  there 
are  several  or  many  points  or  spots  of  inflammation 
scattered  through  the  choroid  (Plate  XL).  If  one 
large  area  of  the  choroid  is  alone  involved  this  is 
called  diffuse.  Diffuse  choroiditis  (also  called 
deep  choroiditis)  may  result  from  several  dissemi- 
nated areas  enlarging  and  coming  together.  Cir- 
cumscribed choroiditis  means  an  inflammation 
more  or  less  limited  in  extent,  whereas  macular  or 
central  choroiditis,  while  it  may  be  circumscribed, 
means  an  inflammation  at  the  macular  region. 
Senile  choroiditis,  as  its  name  indicates,  is  choroid- 
itis in  the  aged  and  is  usually  a  variety  of  central 
or  macular  choroiditis.  Recent  and  old  choroiditis 
are  other  names  given  to  the  acute  and  chronic 
varieties,  and  atrophic  choroiditis  is  but  the  final 
stage  of  the  disease.  Myopic  or  posterior  choroid- 
itis is  usually  a  choroiditis  seen  in  eyes  which  have 
a  high  myopic  refraction,  and,  as  its  name  implies, 
is  in  the  posterior  part  of  the  eye  and  usually 
begins  at  the  temporal  side  or  edge  of  the  disc, 
and  is  called  the  myopic  crescent  from  its  fre- 
quent resemblance  to  a  crescent;  or,  if  the  cho- 
roiditis surrounds  the  disc,  it  is  called  annular, 


PLATE  XI. 

RETINO-CHOROIDITIS    (SPECIFIC).     FUNDUS   OF  LEFT   EYE.     DIRECT 

METHOD. 

Mr.  E.    Aged  39  years. 

History.  Failing  vision  was  noticed  three  days  before  coming 
under  observation.  Thought  it  was  only  a  cold  in  his  eye,  as  he 
had  iritis  and  cyclitis  as  complications. 

Fundus  Changes.  Nasal  edge  of  disc  hidden  and  cannot  be  dis- 
tinguished from  the  neighboring  retina.  Temporal  edge  of  disc  is 
clear  and  reveals  a  narrow  crescent.  A  few  yellowish-colored  spots 
seen  in  the  choroid.  Other  spots  of  choroiditis  have  become  absorbed 
and  white  areas  (atrophy)  have  taken  their  places  with  irregular  pig- 
mentations. The  choroidal  circulation  is  exposed  in  the  periphery. 
A  large  patch  of  retino-choroiditis  is  seen  close  to  the  temporal  side 
of  the  disc.  Vision  is  very  much  reduced  and  the  patient  depends 
on  the  vision  of  the  right  eye,  which  is  VI/IX  and  was  not  so 
seriously  disturbed. 


264 


PLATE    XI 


Retina-  Charm  ditis 


DISSEMINATED    CHOROIDITIS.  267 

and  if  there  is  any  bulging  backward  of  the  sclerotic 
coat,  it  is  called  a  posterior  staphyloma.  Syphilitic 
choroiditis  is  named  from  its  cause  and  may  mean 
any  one  of  the  varieties  mentioned,  though  the  dif- 
fuse or  circumscribed  variety  is  usually  understood. 
Disseminated  Choroiditis  (Plate  XL).  This 
is  recognized  as  the  most  common  form  of  choroid- 
itis. The  spots  of  inflammation  are  scattered  (dis- 
seminated) over  the  eye  ground  chiefly  in  the 
periphery.  These  areas  are  at  first  yellowish  in 
color,  slightly  elevated,  more  or  less  oval  in  shape. 
As  these  inflammatory  exudates  become  absorbed 
the  choroidal  tissue  is  also  absorbed  or  destroyed, 
the  white  sclera  showing  in  its  place,  and  pigment 
massings  surround  many  of  the  irregular  areas. 
These  areas  of  absorption  have  the  appearance  as 
if  parts  of  the  choroid  had  been  punched  out  by  an 
instrument  which  was  not  clean,  and  therefore  had 
left  black  edges.  In  other  instances,  or  even  in  the 
same  choroid,  the  exudates  may  be  replaced  by  a 
large  spot  of  pigment,  or  possibly  by  several  spots 
which  may  coalesce,  forming  one  large,  or  several 
large,  patches.  In  some  instances  irregular  figures 
may  be  depicted.  The  choroid  between  the  patches 
is  seen  to  be  apparently  healthy.  The  optic  disc  is 
seen  to  be  atrophic  in  the  late  stages  of  severe  cho- 
roiditis, and  the  term  secondary  optic  atrophy  has 
been  given  to  this  condition.  Both  eyes  are  usually 
affected,  often  one  eye  being  affected  in  advance 
of  its  fellow. 


268  THE   OPHTHALMOSCOPE. 

Causes.  Syphilis  is  recognized  to  be  the  most 
common  cause  of  this  disease  whether  acquired  or 
inherited.  Other  causes  may  be  looked  for  in  gen- 
eral diseases,  scrofula,  anemia,  chlorosis  and  also 
in  myopia.  Sometimes  the  cause  cannot  be  de- 
termined. 

Symptoms.  These  are  principally  those  of  de- 
fective vision  and  as  the  retina  and  vitreous  are 
implicated  the  descriptions  of  the  patient  are  in- 
dicative of  the  structure  or  structures  involved. 
Floating  specks  indicate  vitreous  opacities,  and 
distortion  of  objects  (metamorphopsia)  when 
the  edge  of  a  door  frame  or  a  straight  line  ap- 
pears bent,  indicates  that  the  retinal  elements 
are  separated  or  crowded  together  by  being 
raised  up  by  an  exudate.  Central  and  peripheral 
vision  are  impaired  according  to  the  amount 
of  structure  disturbed  and  also  its  location  in 
the  fundus.  Scotomata  are  quite  in  evidence,  but 
not  so  annoying  when  in  the  periphery  as  when 
they  crowd  upon  the  macular  region. 

Course  of  Choroiditis.  This  is  usually  a  chronic 
condition,  taking  many  weeks  or  months  for  the 
exudates  to  be  absorbed.  Atrophy  of  the  retina 
and  the  disc  are  liable  to  eventually  make  the  case 
worse,  especially  if  the  choroiditis  has  been  exten- 
sive. Cataract  is  not  an  infrequent  complication 
late  in  the  disease. 

Prognosis.  This  depends  ( i )  on  the  portion  of 
the  choroid  involved,  (2)  on  the  extent  of  the  in- 


TREATMENT    OF    CHOROIDITIS.  269 

flammation,  and  (3)  on  the  cause  of  the  choroid- 
itis.  If  the  periphery  of  the  choroid  alone  is  in- 
volved, central  vision  may  remain  good,  but  if  the 
inflammation  involves  the  macula  or  its  vicinity, 
the  prognosis  for  useful  vision  must  be  guarded. 
When  caused  by  syphilis,  and  the  patient  is  seen 
early  and  placed  under  prompt  and  vigorous  anti- 
syphilitic  treatment,  the  case  will  be  quite  favorable 
for  useful  vision  if  the  macula  has  not  been  in- 
volved. 

Treatment.  If  caused  by  syphilis  this  must  be 
treated  energetically  with  mercurial  inunctions, 
large  and  increasing  doses  of  the  iodids,  pilocar- 
pin  sweats,  etc.  If  the  choroiditis  is  caused  by 
anything  else,  it  must  be  treated  according  to  its 
cause.  It  is  a  noteworthy  fact  that  no  matter  what 
the  cause,  the  alernative  treatment  with  mercury 
and  the  iodids  is  often  the  best  treatment.  This 
should  be  borne  in  mind,  as  valuable  time  might  be 
lost  if  the  physician  was  not  on  his  guard  in  finding 
the  cause,  or  not  disposed  to  believe  that  the  indi- 
vidual could  be  subject  to  syphilis. 

Aside  from  the  systemic  treatment  the  eyes 
should  be  protected  from  bright  lights  with  dark 
glasses,  and  the  accommodation  put  at  rest  with  a 
properly  selected  cycloplegic. 

Diffuse  Choroiditis.  (Also  called  deep  and 
exudative  choroiditis.)  This  is  practically  a  sub- 
division of  the  disseminated  variety.  The  ophthal- 
moscope reveals  large  areas  of  yellowish-white 


270  THE    OPHTHALMOSCOPE. 

exudates ;  these  may  be  scattered  or  they  may  coal- 
esce. If  the  retina  becomes  involved,  as  it  often 
does  by  contiguity  of  structure,  the  condition  is 
one  of  choroido-retinitis,  and  the  opaque  retina 
adds  its  quota  to  the  characteristic  picture.  In  this 
condition  of  choroido-retinitis  pigment  may  be  seen 
here  and  there  upon  the  retinal  vessels.  When  ab- 
sorption or  atrophy  of  the  yellowish  areas  takes 
place,  the  sclera  becomes  exposed  in  large  or  small 
areas  with  irregular  patches  of  pigment  at  the 
edges,  or  irregularly  scattered.  Often  they  assume 
an  oval  or  circumscribed  appearance. 

Course,  prognosis  and  treatment  are  the  same 
for  diffuse  choroiditis  as  for  the  disseminated 
choroiditis. 

Central  Choroiditis.  (Also  called  macular  or 
senile.)  This  is  usually  a  condition  of  both  eyes. 
As  it  involves  the  macular  region  the  vision  is  usu- 
ally seriously  diminished,  with  resulting  scotoma. 
The  disease  is  recognized  in  several  varieties ;  there 
may  be  an  atrophic  patch  with  surrounding  pig- 
ment at  the  macula,  or  there  may  be  a  large  white 
area  at  the  macula  in  which  choroidal  vessels  may 
be  seen.  Another  variety  is  known  as  "  Tay's 
choroiditis"  or  "  Tay's  dots";  these  are  many 
small,  white,  glistening  dots  (called  senile  guttate 
choroiditis),  and  are  due  to  colloid  degeneration. 

Causes.  Trauma  and  syphilis  and  ametropia  are 
the  commonly  recognized  causes.  Senile  choroid- 
itis does  not  appear  to  be  benefited  by  treatment. 


MYOPIC    CHOROIDITIS.  2/1 

When  caused  by  syphilis  and  ametropia  the  treat- 
ment is  self-evident. 

Myopic  Choroiditis.  Usually  this  is  a  very 
serious  condition,  and  means  that  the  condition 
has  been  brought  about  by  a  stretching  or  elonga- 
tion of  the  eyeball  and  as  its  name  indicated  the 
eye  is  myopic.  The  choroiditis  begins  usually  or 
almost  invariably  on  the  temporal  side  of  the  disc 
and  advances  toward  the  macula  and  may  destroy 
it  and  pass  beyond.  The  choroiditis  may  encircle 
the  disc  at  the  same  time.  The  choroidal  vessels 
become  exposed,  the  retina  atrophies  and  the  pig- 
ment becomes  scattered  irregularly.  Vitreous 
opacities  are  innumerable  and  of  various  sizes  and 
forms,  the  vitreous  itself  becoming  quite  fluid. 
The  vision  is  very  much  reduced  and  detachment 
of  the  retina  and  the  development  of  cataract  may 
soon  complicate  the  already  "  sick  "  eye.  The 
treatment  resolves  itself  into  rest  of  the  eye  for  all 
near  work,  protection  from  bright  lights,  and  care- 
ful attention  to  the  general  health  and  later  to 
the  correction  of  the  refractive  error  with  careful 
instructions  to  the  patient  to  use  his  eyes  as  little 
as  possible.  Internally  alterative  treatment  occa- 
sionally does  much  good. 

Colloid  degeneration  of  the  choroid,  also  called 
guttate  choroiditis,  is  an  extremely  rare  condition 
and  is  recognized  as  occurring  in  the  macular 
region.  The  ophthalmoscope  reveals  many  round 
elevated  spots  or  bodies,  placed  close  together,  they 


2J  2  THE    OPHTHALMOSCOPE. 

are  semi-transparent,  and  have  been  compared  by 
their  resemblance  to  a  mulberry.  It  is  a  condi- 
tion of  both  eyes,  but  one  of  the  eyes  may  be 
more  involved  than  its  fellow.  The  vision  is 
often  impaired.  There  is  no  treatment  for  the 
condition  other  than  prescribing  the  necessary 
glasses. 

Irido-choroiditis  (also  called  panophthalmitis, 
metastatic,  purulent  or  suppurative  choroiditis)  is 
an  acute  inflammation  of  the  choroid  pursuing  a 
rapid  course,  and  caused  by  purulent  matter  being 
carried  into  the  choroid.  No  satisfactory  study  of 
the  choroid  can  be  made  out  unless  the  disease 
comes  under  observation  quite  early  and  yields 
to  prompt  treatment.  The  areas  of  purulent  exu- 
date  seen  in  the  choroid  soon  coalesce  and  at  the 
same  time  the  retina  and  vitreous  become  involved. 
With  a  strongly  reflected  light  a  large  yellowish 
mass  may  be  seen  in  the  vitreous,  and  no  clear  view 
of  the  fundus  is  made  out.  Iritis,  cyclitis,  etc.,  are 
early  manifestations  which  go  to  make  up  the  true 
picture  of  panophthalmitis.  External  manifesta- 
tions of  panophthalmitis  are  swollen  lids,  the  con- 
junctiva edematous  and  possibly  protruding 
between  the  lids,  the  cornea  appearing  to  be  buried 
in  the  swollen  conjunctiva.  The  patient  complains 
of  pain  and  loss  of  sight,  and  the  temperature  is 
elevated. 

Causes.  Purulent  matter  carried  into  the  eye 
by  the  blood  vessels  or  germs  entering  the  eyeball 


RUPTURE    OF    CHOROID.  273 

from  perforating  wounds  or  ulcers.  Puerperal 
sepsis ;  meningitis ;  small-pox,  etc. 

Prognosis.  This  must  be  very  guarded.  Either 
blindness  with  shrinking  of  the  globe  (phthisis 
bulbi)  or  enucleation  will  be  the  usual  and  final 
result  of  panophthalmitis. 

Treatment.  Careful  attention  to  local  and  con- 
stitutional symptoms.  Atropin  instillations,  cold 
compresses  medicated  with  bichlorid  of  mercury 
1-2,000,  blood-letting  from  the  temple,  enucleation, 
if  there  is  not  much  hope  of  saving  the  eye  by  rea- 
son of  pain  (glaucoma),  pus  in  the  anterior  cham- 
ber, and  orbital  cellulitis  or  cerebral  meningitis 
threatening. 

Rupture  of  the  Choroid.  This  usually  takes 
place  as  a  result  of  a  blow  on  the  eye  and  is  recog- 
nized by  a  tear  or  rent  in  the  choroid,  resembling 
in  shape  a  new  moon;  the  hollow  or  concavity  of 
the  crescent  with  irregularly  pigmented  edges  is 
toward  the  disc,  the  crescent  itself  is  yellowish- 
white,  this  color  resulting  from  a  partial  exposure 
of  the  sclera.  The  common  location  of  the  rup- 
ture is  to  the  temporal  side  of  the  disc.  If  the 
retina  was  not  injured,  or  only  partly  so,  at  the 
time  the  choroid  was  ruptured,  some  of  the  retinal 
vessels  may  be  seen  passing  over  the  crescent.  At 
the  time  of  rupture  or  soon  afterwards  the  rupture 
may  be  covered  with  a  hemorrhage,  and  hence 
the  picture  just  described  cannot  be  definitely 
studied  with  the  ophthalmoscope  until  after  ab- 


2/4  THE    OPHTHALMOSCOPE. 

sorption  of  the  clot.  The  rupture  may  lie  close  to 
or  at  some  distance  from,  the  disc,  depending  on  the 
character  of  the  injury.  The  vision  may  be  seri- 
ously impaired  if  the  rupture  is  at,  or  close  to,  the 
macula. 

Treatment.  Cold  compresses  and  a  cycloplegic 
if  seen  early.  The  injury  is  permanent  and  the 
vision  is  disturbed  accordingly. 

Sarcoma  of  the  Choroid.  When  seen  with 
the  ophthalmoscope  there  is  an  elevation  of  the 
retina  and  the  growth  beneath  appears  brownish 
or  black,  or  white  in  color ;  it  is  a  melino-sarcoma  if 
dark  in  color  and  a  leuco-sarcoma  if  white.  Melino- 
sarcoma  is  much  more  common,  the  leuco-sarcoma 
being  very  rare.  This  growth  is  usually  situated  to 
the  temporal  side  of  the  disc  and  may  appear  as  far 
forward  as  the  ciliary  body.  The  detached  retina 
if  seen  when  the  sarcoma  is  small,  is  applied  equally 
to  the  surface  of  the  growth  and  does  not  tremble 
or  have  the  characteristic  wave  motion  that  is  im- 
parted to  the  retina  when  the  eye  is  rotated  and 
there  is  fluid  beneath  the  retina  (see  Detachment 
of  the  Retina).  Sarcoma  of  the  choriod  is  a  rare 
disease,  most  unusual  in  children  and  usually  oc- 
curs in  adults  past  forty  years  of  age. 

Symptoms.  The  patient  notices  a  defect  in 
vision  which  the  ophthalmoscope  usually  reveals 
as  detachment  of  the  retina.  This  is  one  of  the 
first  indications  of  the  disease.  As  the  sarcoma  de- 
velops there  is  an  increase  in  the  size  of  the  detach- 


TUBERCULOSIS    OF    CHOROID.  275 

ment  and  an  increase  in  the  tension  together  with 
pain  (glaucoma  absolutum).  The  sarcoma  may  or 
may  not  break  through  the  sclera,  but  other  organs 
of  the  body,  especially  the  liver,  may  suffer  by 
metastasis. 

Prognosis.  Most  unfavorable.  The  eye  must 
be  enucleated  at  once  but  this  is  no  guarantee  that 
metastasis  has  not  already  taken  place. 

Treatment.  Prompt  enucleation  and  dividing 
the  nerve  as  far  back  as  possible.  If  the  orbital 
tissue  is  involved  this  must  be  removed,  including 
the  periosteum  if  necessary  and  following  this  later 
with  the  employment  of  the  X-rays. 

Tuberculosis  of  the  Choroid.  This  occurs  either 
as  the  disseminated  (miliary)  tubercle  or  as  a  soli- 
tary (conglobate)  tubercle.  The  former  appears 
as  small  round  elevated  spots  of  a  pale  red  color 
and  grow  rapidly.  They  appear  in  subjects  who 
have  acute  miliary  tuberculosis,  and  are  not  often 
seen  in  chronic  tuberculosis.  Solitary  tubercle  ap- 
pears as  a  large  mass  which  is  virtually  an  accumu- 
lation of  many  small  nodules.  This  is  a  disease  of 
young  subjects.  The  prognosis  is  very  unfavor- 
able for  the  eye  and  the  patient.  The  treatment  re- 
solves itself  into  the  systemic  treatment  of  the  pa- 
tient and  enucleation  of  the  eye. 


Glaucoma  (yXavKo?,  sea  green). 

A  disease  of  the  eye,  so-called  originally  on 
account    of   a    greenish    reflex   occasionally    ob- 


276  THE    OPHTHALMOSCOPE. 

tained  from  the  pupillary  area.  A  very  bad 
name,  therefore,  as  it  does  not  explain  anything 
about  the  disease,  and  in  fact  a  greenish  pupillary 
reflex  may  be  seen  in  certain  conditions  of  the  lens 
and  not  necessarily  in  glaucomatous  eyes.  Glau- 
coma, as  now  universally  understood  from  one  of 
its  chief  signs,  is  a  disease  characterized  by  an  in- 
crease in  the  intra-ocular  contents,  and  this  is 
spoken  of  and  known  as  "  tension." 

Causes.  The  causes  of  increase  in  the  intra- 
ocular contents  is  either  hypersection  of  the  intra- 
ocular fluids  or  a  blocking  or  stoppage  of  the  ex- 
cretory passages,  or  both  conditions  together.  Just 
which  of  these  causes  precipitates  the  attack  can- 
not always  be  determined  in  each  instance,  but 
there  is  hardly  any  doubt  but  that  secretion  is  go- 
ing on  while  the  excretory  passages  are  blocked, 
and  this  explains  many  of  the  other  symptoms  of 
the  disease. 

The  lymph  stream  of  the  eye  flows  from  the 
vitreous  through  the  zonula  of  Zinn  into  the  pos- 
terior chamber,  through  the  pupil  into  the  anterior 
chamber,  and  hence  into  the  angle  of  the  anterior 
chamber,  into  the  canals  of  Fontana  and  the  canal 
of  Schlemm,  then  into  the  lymph  channels  exter- 
nally. Any  obstruction  to  the  onward  flow  of  this 
stream,  means  pressure  of  the  intra-ocular  contents 
against  the  sensitive  nerves  and  the  rigid  outer 
tunic  of  the  eye,  with  resulting  symptoms. 

Inspection  shows  the  vessels  of  the  ocular  con- 


PLATE   XII. 
GLAUCOMA.    FUNDUS   OF   LEFT   EYE.     DIRECT   METHOD. 

W.  W.  D.     Aged  40  years.     Salesman. 

History.  Vision  of  left  eye  was  never  as  good  as  that  ftf  the 
right.  Has  always  worn  glasses  for  "  farsightedness."  Never  any 
severe  pain  in  left  eye,  and  only  lately  has  noticed  that  the  vision 
was  getting  much  worse  and  the  eye  deviating  outward. 

Vision  of  left  eye  equals,  seeing  very  large  objects,  or  counting 
fingers  at  about  twelve  inches  distant.  Eccentric  fixation  (periph- 
eral vision). 

Fundus  Changes.  Edge  of  disc  seen  with  -f  6  D.  and  the  bottom 
of  the  cup  is  seen  with  a  —  5  D.  Vessels  of  the  retina  disappear  as 
they  pass  into  and  around  the  edge  of  the  disc,  and  are  out  of  focus 
when  they  reach  the  bottom  of  the  cup,  where  they  appear  indis- 
tinctly at  the  nasal  side.  The  nerve  is  bluish  or  pearly  white  in 
color  and  atrophic  (glaucoma  atrophy).  The  edges  of  the  disc  have 
a  distinctly  yellowish  color  and  the  pigment  is  broken  into  fine  par- 
ticles. There  is  a  peculiar  redness  showing  at  the  macula.  . 

The  cupping  embraces  the  entire  disc. 

Right  eye  vision  equals  VI/VI  with  -|-  5  D.  Glaucoma  not 
present. 


278 


PLATE    XII 


Glaucoma 


SYMPTOMS.  28l 

junctiva  tortuous,  appearing  like  fine  corkscrews. 
The  cornea  becomes  cloudy,  appearing  like  a  piece 
of  glass  that  has  been  breathed  upon,  and  is  more  or 
less  anesthetic.  The  anterior  chamber  is  shallow, 
the  iris  appearing  nearer  to  the  cornea  than  in 
health.  The  pupil  is  dilated.  The  cornea  being 
cloudy  and  the  large  pupil  being  black  the  observer 
may  obtain  at  times  and  in  certain  lights  a  greenish 
reflex  from  the  pupillary  area. 

Subjective  Symptoms.  Pain  in  the  eyeball 
which  may  extend  to  the  forehead,  corresponding 
to  the  eye  involved,  and  also  to  the  cheek  bone  and 
same  side  of  the  nose,  if  the  attack  is  unusually  se- 
vere. There  is  more  or  less  dimness  of  vision  de- 
pending also  upon  the  severity  of  the  attack  and 
the  dimness  of  vision  may  be  particularly  marked 
in  the  nasal  field.  The  patient  notices  halos  (rings 
of  various  colors)  about  any  light. 

Objective  Symptoms.  The  tension  of  the  eye- 
ball is  harder  than  normal.  The  beginner  will  ap- 
preciate this  by  testing  the  tension  of  his  own  nor- 
mal eye,  by  alternately  pressing  the  ends  of  his 
index  fingers  on  his  own  eye  through  the  upper  lid 
as  the  closed  eye  is  directed  downward,  and  then 
testing  the  tension  of  the  patient's  eye  in  like  man- 
ner; or  alternately  testing  the  patient's  eyes,  as  it 
is  not  customary  to  find  both  eyes  of  the  patient 
exactly  the  same  or  equally  affected,  at  the  same 
time. 

Ophthalmoscopic  Changes  (Plate  XII.).  If 
23 


282  THE   OPHTHALMOSCOPE. 

the  media  are  not  too  cloudy  the  observer  will  see 

1 i )  the  disc  excavated  or  cupped,  this  cupping  ex- 
tending to  the  edge  of  the  disc  and  the  edges  being 
quite  abrupt  or  overhanging,  and  the  disc  edges  sur- 
rounded by  a  yellowish  halo  or  glaucomatous  ring; 

(2)  the  vessels  in  the  retina  as  they  are  traced  to  the 
edge  of  the  disc  (cup)  bend  at  right  angles,  and  if 
seen  at  the  bottom  of  the  cup,  are  crowded  more  or 
less  to  the  nasal  side  and  are  no  longer  in  focus  as 
compared  with  the  strength  of  lens  required  to  see 
the  vessels  as  they  appeared  at  the  edge  of  the  disc ; 

(3)  the  arteries  are  seen  to  pulsate  at  the  edge  of 
the  cup. 

Diagnosis.  Hazy  cornea;  and  also  anesthesia 
of  the  cornea ;  this  latter  is  proven  by  touching  the 
cornea  with  a  small  or  narrow  thread  or  piece  of 
cotton  drawn  to  a  fine  point  and  made  to  touch  the 
cornea  as  the  lids  are  kept  wide  open,  the  patient 
not  being  conscious  of  the  contact;  anterior  cham- 
ber shallow ;  pupil  dilated  4  or  5  millimeters ;  pain ; 
increased  tension ;  cupping  of  the  disc ;  arterial  pul- 
sation ;  halos  and  dimness  of  vision  and  diminution 
of  the  field  of  vision;  range  of  accommodation  di- 
minished. 

Glaucoma  seldom  develops  before  the  age  of 
twenty-five.  Both  eyes  may  be  affected,  but  usu- 
ally one  is  often  affected  long  before  its  fellow. 
Myopic  eyes  seldom  develop  glaucoma ;  therefore  it 
is  much  more  common  in  eyes  that  are  hyper- 
metropic. 


GLAUCOMA.  283 

Varieties  of  Glaucoma.  These  are  many.  Pri- 
mary and  secondary;  primary  glaucoma  develops 
without  any  previous  disease  of  the  eye,  whereas 
secondary  glaucoma  develops  as  a  consequence  of 
a  previous  disease  (iritis,  cyclitis,  uveitis,  injuries, 
etc.).  Primary  glaucoma  is  recognized  in  three 
forms:  acute,  inflammatory  and  chronic  non- 
inflammatory; this  latter  is  also  called  simple 
chronic  glaucoma.  The  chronic  inflammatory  va- 
riety is  also  called  subacute  or  chronic  congestive 
glaucoma. 

Differential  Diagnosis — Acute  Inflammatory 
Glaucoma,  (i)  Sudden  onset;  (2)  intense  pain; 
(3)  marked  inflammation  of  eyeball;  (4)  in- 
creased tension.  May  terminate  ( i )  in  total  blind- 
ness in  a  few  hours  (glaucoma  fulminans  or  malig- 
nant glaucoma).  (2)  After  several  attacks  the 
eyeball  may  remain  stony  hard  and  blindness  re- 
sult (stone  blind)  (glaucoma  absolutum)  ;  or  (3) 
if  inflammation  persists  the  condition  is  one  of 
chronic  inflammatory  glaucoma. 

Chronic  Non-Inflammatory  (Simple  Chronic 
Glaucoma) .  This  is  the  very  opposite  of  the  acute 
inflammatory  variety,  as  it  is  very  insidious  or  slow 
in  its  development,  and  patients  occasionally  verge 
onto  blindness  before  coming  under  observation. 
This  variety  might  be  overlooked  or  mistaken  for 
optic  atrophy,  if  it  were  not  for  the  cupping  of  the 
disc. 

Prognosis.    The  earlier  the  case  comes  under 


284  THE   OPHTHALMOSCOPE. 

observation  and  treatment,  the  better,  and  the  more 
favorable  the  prognosis,  and,  vice  versa,  the  longer 
the  treatment  is  delayed  the  more  unfavorable  the 
case  becomes  and  blindness  may  result  as  also  loss 
of  the  eye.  Acute  and  uncomplicated  glaucoma 
receiving  prompt  treatment  gives  a  favorable  prog- 
nosis. Cases  of  chronic  glaucoma  do  not  offer  a 
very  encouraging  prognosis ;  considerable  degener- 
ation has  very  likely  taken  place  and  the  field  of 
vision  has  very  likely  been  cut  down  and  visual 
acuity  diminished. 

Treatment.  This  resolves  itself  into  the  sur- 
gical, local  medication,  and  internal  treatment. 
The  surgical  treatment  is  that  of  iridectomy.  The 
local  medication  is  by  myotics,  drugs  which  con- 
tract the  pupil  and  therefore,  if  possible,  draw  the 
iris  away  from  the  angle  of  the  anterior  chamber, 
whereas  if  left  alone  and  a  myotic  is  not  used  the 
iris  is  likely  to  adhere  and  block  the  canals  of 
Fontana  and  Schlemm.  Of  the  myotics,  eserin 
in  the  strength  of  J/£  to  2  grains  of  the  sulphate 
to  an  ounce  of  water  may  be  prescribed,  and  one 
drop  of  this  solution,  dropped  into  the  eye  every 
three  or  four  hours  until  the  tension  is  reduced, 
and  then  to  be  instilled  three  times  a  day.  Pilo- 
carpin  nitrate  in  similar  strength  or  stronger 
may  be  used  in  place  of -the  eserin.  Knowing 
the  decided  danger  or  tendency  for  glaucoma  to 
affect  the  fellow  eye,  it  is  good  practice  to  use  the 
myotic  in  both  eyes,  but  not  quite  so  freely  in  the 


GLAUCOMA.  285 

unaffected  eye.  It  is  also  good  practice  to  combine 
an  equal  amount  of  cocain  with  the  myotic,  as  the 
myotic  is  thereby  more  readily  absorbed.  If  the 
pain  is  unusually  severe  and  does  not  yield  after  a 
few  instillations  of  the  myotic,  it  may  be  necessary 
to  apply  hot  fomentations  (cloths  wrung  out  of  hot 
water),  to  draw  blood  from  the  temple  with  the 
natural  or  artificial  leach,  and  also  to  give  a  hypo- 
dermic of  morphia.  Internally  the  salicylate  of 
soda  should  be  given  in  large  doses  frequently  re- 
peated. The  bowels  should  be  kept  open.  Gentle 
massage  of  the  eye  through  closed  lids  is  good  prac- 
tice, as  it  often  does  good,  but  must  not  be  severe  or 
persisted  in  if  the  pain  is  increased  thereby. 
Whether  the  local  or  internal  treatment  gives  relief 
or  not  it  is  wise  to  perform  an  iridectomy  as  soon 
as  possible. 

Secondary  Glaucoma.  This  variety  of  glau- 
coma, as  its  name  implies,  is  brought  about  by  a 
previous  injury  or  disease,  namely,  iritis,  cyclitis, 
swollen  or  dislocated  lens,  etc. 

Treatment.  This  is  practically  the  same  as  for 
primary  glaucoma.  The  swollen  or  dislocated  lens 
should  be  removed  if  it  is  the  cause  of  the  glau- 
coma. When  the  glaucoma  is  brought  about  by  ad- 
hesion of  the  iris  to  the  lens  capsule  (iris  bombe) 
an  iridectomy  or  iridotomy  must  be  performed. 
Eyes  with  absolute  glaucoma  require  enucleation 
for  relief  of  the  pain. 


INDEX. 


Absolute   scotoma,    147 

Accommodation,    18,   22 

Acuity  of  vision,  140,  141 

Aerial  image,  30,  32 

Albinism,  106 

Albino,  9,  106 

Albuminuric    retinitis,    193,    194, 

195    (Plate   IV.) 
atypical  forms,  196 
of  pregnancy,  196  (Plate  V.) 
Amaurotic    cat's    eye,    224 
family  idiocy,  227,  228 
Amblyopia,  toxic,  245,  246 
Aneridia,  100 
Anemia  of  retina,  162,  163 
causes   of,    167 
treatment  of,   167 
Aneurism  of  retinal  vessels,  153, 

154 

Angioid  streaks,  228 
Anomalies,     congenital,     98,    99, 
loo,  101,  102,  103,  104,  105,  106, 
107 

Anterior  polar  cataract,  102,  103 
Apoplexy  of  the  retina,  186,  187 

(Plate  III.) 
cause  of,  187 
prognosis,  187 
treatment,    187 
Aqueous  humor,  79,  131 

oblique   illumination,  37,  38, 

39,  40,  41,  42 

ophthalmoscopic  examination 
of,  13,  14,  26 

287 


Arcus  senilis,  128 
Argand  burner,  n 
Argyll-Robertson  pupil,   252 
Arterial  pulsation,  184,  282 
Arterio-sclerosis,   151,   152 
Artery,  central,  113,  122 
decrease  in  size  of,  151 
embolism  of  (Plate  II.) 
increase  in  size  of,  150 
persistent   hyaloid,    105,    106 
Ascending  neuritis,  238,  239 
Astigmatism,   74 

compound  hypermetropic,  75 
compound  myopic,  75 
mixed,  76 

simple  hypermetropic,  75 
simple  myopic,  75 
Atrophic  cup,  233 
Atrophy  of  the  choroid,  261 
of  the  disc,  162,  163,  238 
of  the  optic  nerve,  246,  247 
(Plate  IX.),  248  (Plate 
X.),  252,  257,  258 
cause  of,  257 
diagnosis   of,   258 
prognosis,  258 
treatment,    258 
primary,    255 
retina  of  the,  271 
secondary,  255 

Atypical    forms    of    albuminuric 
retinitis,  196 


Beam  of  light,  48 


288 


INDEX. 


Black  appearance  of  the  pupil,  9 
Blindness,  160,  161 
Blind  spot,   HI,   146 
Blood-vessels,    121,    127 

new  formed,  152,  153 
Bracket,  10,  11 
Brain  tumor,  195 
Bright's  disease,  193,  194 

retinitis  due  to,  193,  194 
Briicke's  muscle,  90 


Cataract,  anterior  polar,  102,  103 

black,  134 

choroidal,  102,  134 

cortical,  102,  134 

lamellar,    102,    103 

Morgagnian,   134 

nuclear,  133 

posterior  polar,  102,  103 

pyramidal,   102 

ripe,  102 

secondary,  271 

senile,   102,   134 

traumatic,  134 
Catoptrics,  49,  50 
Central  artery,  embolism  of,  164 
(Plate  II.) 

thrombosis   of,    164 
Cherry  red  spot  (Plate  II.) 
Chimney,  cover,  10,  u,  42 
Choked  disc,  235,  236,  237,  238, 

239 

Cholesterin  crystals,  139 
Choroid,  84,  126 

anatomy  of,  84,  85,  86 

atrophy  of,  261 

changes  in  color,  259,  260 

colloid   disease   of,    271,    272 

coloboma   of,    105 

degeneration   of,   in   myopia, 
271 


Choroid,    diseases    of    (Chapter 

X.) 

hemorrhage  in,  261 
hyperemia  of,  260 
inflammatory     products     in, 

200 

pigmentation  of,  126,  260 

rupture  of,  273,  274 

suppurative,  272 

sarcoma  of,  274 

tigree,  127 

tubercle  of,  275 
Choroidal  atrophy,  261 

ring,   116,   117 

vessels,    127 
Choroiditis,  261   (Plate  XL) 

central,  262,  270 

changes  in  lens  and  iris  in, 

271 

in   retina   and    disc,   271 
in  vitreous,  271 

diffuse,  269,  270 

disseminated,  262,  267 
cause  of,  268 
prognosis  of,  268,  269 
treatment  of,  269 

exudative,   263 

guttate,  262,  270 

macular,  270 

metastatic,  262 

myopic,   262,  271 

old,  262 

plastic,  262 

posterior,  262 

purulent,  262,  272,  273 

recent,  262 

senile,  262,  270 

syphilitic,  262 

varieties  of,  262 

with  descemetitis,  272 
Choroido-retinitis   (Plate  XI.) 
Cicatricial  bands  in  retina,  153 


INDEX. 


289 


Ciliary  body,  89,  90 

Cilioretinal  vessels,   124 

Circinate  retinitis,  226,  227 

Cloquet's  canal,  106 

Cocain,  16,  17 

Colloid   disease    of   the   choroid, 

271,   272 

Coloboma  of  the  choroid,  105 
of  disc,  105 
of  iris,   100 
of  lens,   105 

Color  of  disc,  112,  121,  229,  230 
Color  of  fundus,  108,  109,  125 

affected     by     light     em- 
ployed, 109 
in  dark  eyes,   109 
in  fair  eyes,   109 
in  mulatto,  109 
of  various  areas,  109,  no 
Compound  astigmatism,  75 

lens,  70 

Concave  mirror,  52,  53,  54 
Condensing  lens,  30.  31,  32,  33 
Congenital    anomalies,    99,     100, 
101,  102,  103,  104,  105,  106,  107 
Conjugate   foci,   53,  63,  64 
Connective  tissue  on  disc,  107 
Corectopia,    101 
Cornea,  81,  82,  83 

anatomy  of,  81,  82,  83,  84 
oblique    examination    of,   37, 

38,  39,  40,  41.  42 
ophthalmoscopic  examination 

of,  13,  14,  26 

smoky  appearance  of,  128 
reflex,  126 

Cover  chimney,   10,    n,  42 
Crescent,    116 

myopic,  116,   118.  271 
Cribrosa.  lamina,   115 
Cup,  atrophic,  233 
glaucoma.   233 
24 


Cup,  physiologic,  113,  114,  233 
to    estimate    depth    of,    114, 

US,  267 
Cupping,  diagnosis  of  normal  and 

abnormal,  114,  115,  234,  235 
Cycloplegic,  15,  16,  17,  18 
Cylinders,  68,  69,  70 
Cysticercus,    139 

D 

Dark-room,  9,  TO 

Davis,  Dr.  E.  P.,  198 

Descemetitis,  128 

de  Schweinitz,  Dr.  G.  E.,  216 

Detachment   of   the    retina,   219, 
220,    221 

De  Zeng  patent,  6,  7,  8 

Diabetic  retinitis,  206  (Plate  VI.) 
course,   206 
prognosis,  206 
treatment,  211 

Diopters,  67,  68 

Direct   method,   at   a   short  dis- 
tance, 13,  14,  26 
close  to  patient.  23 
enlargement  of  image,  27 
estimation  of  refraction,  72, 

73,  74,  75,  76 
examination  by,  13,  14,  26 
schematic  eye.  15 
Disc,  33,  1 10.  HI   (Chapter  IX.) 
Diseases  of  the  choroid   (Chap- 
ter X.) 
of  the  optic  nerve   (Chapter 

IX.) 

of  the  retina  (Chapter  VIII.) 
of  the  retinal  vessels  (Chap- 
ter   VII.) 
of     the     vitreous     (Chapter 

V.) 

Dislocation  of  the  lens,  102,  Fig. 
63.   135 


290 


INDEX. 


Disseminated     choroiditis,     262 
Distortion  of  objects,  177 
Dots,    185 

Crick's,  185 

Gunn's,  185 

Mooren's,   185 

Nettleship's,  185 

neuritic,  197 

Tay's,  270 

E 

Edema  of  the  retina,  180 
Electric  flash,  160,  161 

retinal    changes    from,    160. 

161 

Electric  light,  u,  12,  160,  161 
Embolism  of  central  artery,  164 
(Plate    II.),    167, 
168,  169 
causes    of,    169 
diagnosis  of,  169 
prognosis,  170 
treatment  of,  170 
Emmetropia,  71,  72,  73 
Entozoa,  131 
Euthalmin,  17 
Eserin,  17 

Examination,  methods  of,  13,  14, 

23,  26,  29,  30,  31,  32,  33,  34 

by  focal  illumination,  37,  38, 

39,  40,  41,  42 
direct  at  short  distance,   13. 

14,    26 

close  to  patient,  23 
indirect,  29,  30,  31,  32,  33,  34 
Excavated    disc,    estimating    ex- 
tent of,   114,   115 
Exudative  choroiditis,   262 
atrophic  stage,  261 
exudative  stage,  262 
Eye  (Fig.  61) 

anatomy  of    (Chapter    III.) 


Eye,  astigmatic,  74 

emmetropic,  71,  72,  73 
hypermetropic,    65,    70,    71 
myopic,  64,  71,  72 
schematic,  14,  15,  20 

F 

Field,  142 

of  vision,  143 

field  chart,  144 

Fixed  opacity,  128,  129 

determining  position   of 

130,   131 

Floating  opacity,  136 
Focal  illumination,  32,  37,  38,  39*, 

40,   41 
Focus,  48,  64 

conjugate,  53,  63,  64 
negative,  65 
ordinary,   64,   65 
real,    48,    49 
virtual,  49 
Foreign    bodies    in    cornea,    128, 

129 

aqueous  humor,  131 
lens,  132,  133 
vitreous,    136,    137 
Fovea  centralis,  97,  125 
Fundus,    108 

normal,  108,  109 
color  of,  108,  109,  125 
in   the   albino,    109 
in  the  blonde,   109 
in  the  mulatto,  109 
reflex,  26,  109,  iio>  ill 

G 

Gas,  10,  ii 

Glaucoma,    15.    16,    Chapter    X. 
(Plate  XIT.).  275.  276,  277 
cause  of,  276 

cup,  232    (Plate  XII.),  233. 
234 


INDEX. 


291 


Glaucoma,  treatment  of,  284,  285 

varieties  of,  283 
Glasses,  correcting,   19 
Glioma,  of  the  retina,  224,  225, 
226 

pseudo,  226,  262 
Gould,  Dr.  G.  E.,  141 
Gunn's  dots,  185 
Guttate  choroiditis,  270 

H 

Hansell,  Dr.  H.  R,  233 
Helmholtz's  ophthalmoscope,  I 
Hemeralopia,  211 
Hemorrhage,  154 

causes    of,    157 

choroidal,  261 

retinal,  154,  155,  156,  157,  186 

subhyaloid,   157 

vitreous,  157 

Hemorrhagic  retinitis,  187,  196 
Hermance,  Dr.  W.  O.,  248 
Homatropin,    18 
Hulings-Jackson,   17 
Hyaloid  artery,   105,   106 
Hyperemia  of  the  choroid,  259, 
260 

of  the  optic  disc,  237 

of  the  retina,  158,  159 
Hypermetropia,   27 

tests  for,  27 
Hyphema,  131 
Hypopion,  131 


Indirect  vision,  142,  143 
Illumination,  10 

candle,  10 

daylight,  10 

electric,  ir,  12 

focal,  37.  38,  39,  40,  41 

gas,  10 


Illumination,  oblique,  37,  38,  39, 

40,  41,  42 

oil,   10 

Welsbach,  u 
Image,  aerial,  30,  32 

formed  by  concave  mir- 
ror, 54,  55,  56 
convex    mirror,    56, 

57 
of    eye    ground,    27,    28, 

36,   37 

formation  of,  32,  66 
inverted,  30,  32 
size  of,  27,  28 
upright,  23,  26,  66 
virtual,  23,  26,  66 
Indirect  method,  29,  30,  31,  32, 

33,  34 
examination   by,   29,   30, 

31,  32,  33,  34 
refraction  by,  35,  36 
value  of,  34,  35,  36 
Intense     light,     effect     of     (Sec 
Electric  and  Snow  Blindness), 
160,  161 

Intensity  of  light,  44,  45 
Interstitial  keratitis,  131 
Intra-ocular  optic  neuritis,  239, 

240 

Irideremia,   100 
Irido-choroiditis,    272 
Irido-donesis,   135 
Iris,  86,  99,  100 

anomalies,  100,  101,  102 
anatomy  of,  86,  87,  88,  89 
changes    in,    132 
congenital  coloboma,  100 
examination  of,  131,  132 

Iris   diaphragm  chimney,   10,   II 
reaction,   132 


292 


INDEX. 


Jennings,  Dr.  J.  E.,  102,  138 

K 

Keratitis,   interstitial,   131 
punctata,  131 


Lamellar  cataract,  102,  103 

Lamina  cribrosa,  96 
vitrea,  85 

Lamp,  electric,  6,  7 
oil,  10 

Lens,  59 

convex,  59,  60,  62,  63 
concave,  60,  61,  62,  63 
coloboma  of,  105 
combinations,   4,   5 
condensing,  30,  31,  32,  33 
crystalline,   92,    93,    94 
cylinder,    68,    69,    70 
dislocation  of,  102,  135 
foreign  bodies  in,  132,  133 
numeration   of,   67,   68 
oblique     illumination     with, 

38,  39 
ophthalmoscopic  examination 

of,  132 

smoky  appearance  of,  132 
varieties  of,  59,  60,  61,  62 

Lenticonus,  104 

Lenticular   opacities,    102 
color  of,  102 
position  of,  102 

Leucoma,  129 

Leukemic  retinitis,  188,  189 

Leucosarcoma,  274 

Light,  10,   ii,  12,  44 
streak,  122 

Locomotor  ataxia,  257 

Loring,  2,  3,  4 

Loring's  ophthalmoscope,  2,  3,  4 


Loupe,  40,  41 

Luminous   ophthalmoscope,  6,   7 

M 

Macula,  22,  97,  129 

appearance  of,  97,  125,  126 

circulation   at,  97,  98 

coloboma  of,   105 

lutea,  97,  125 

reflexes,  125 

region,  97,  126 

symmetric    changes     in    in- 
fancy, 227 

vessels,  97,  98 

Magnification  by  direct  method, 
27 

by  indirect  method,  37 
Magnifying   glass,   31 
Mariotte's  blind  spot,  46 
Margin  of  the  disc,  no 
Media,  27 

of  the  eye,  27 

examination  of,  27 
Medullary     sheaths,      106,     107 

(Plate  IX.) 
Medusa,  240 
Melanosarcoma,  274 
Membrana   cribrosa,    115 
Membrane,  pupillary,   101,   102 
Metamorphopsia,  177 
Metastatic   choroiditis,   262 
Micropsia,   177 
Microphthalmos,   99 
Miliary  tuberculosis,  275 
Mirror,  2 

concave,  2,  12,  13 

reflection    from,    52,    53,    54 

convex,   56 

movement   of,    13,    14 

perforation   in,   2 

plane,  6,  12 

reflection  from,  2,  8,  12 


INDEX. 


293 


Mirror,  retinoscopic,  76 

sight-hole   in,   2,   6 

stationary,  8 

tilting,   2,  7,  8 
Mixed  astigmatism,  76 
Morton's  ophthalmoscope,  2,  5 
Muller's  fibers,  go 
Musser,  Dr.  J.  H.,  248 
Mydriatics,  15,  16,  17,  18 

objections  to,   15,   16,   17,   18 

uses  of,  15,  16 
Myopia,  29 

description   of,   64,   71,   72 

test  for,  71,  72 
Myopic  choroiditis,  271 

crescent,  271 

degeneration  of  the  choroid, 
271 

N 

Nebula,  129 

Negative  focus,  65 

Nerve,  optic,  95,  96 
-fibers,  95,  96 
-head,  96,  97,  100,  m 
diseases  of  (Chapter  IX.) 

Nettleship's  dots,   185 

Neuro-retinitis,  243,  244,  245 

Neuritis,  optic,  239 

interstitial,  244,  245 
retrobulbar,   239,   244,   245 

New  vessels  in  vitreous,  153 

Nicotin,  chronic  poisoning,  245 

Night-blindness,  211 

Normal  eye,  71,  72,  73 
cupping,   113,   114 
fundus.     See  Chapter  IV. 

Nubecula,  129 

Nystagmus,   106 


Object  lens,  30,  31,  32,  33 
handle  for,  31 


Oblique  illumination,  37,  38,  39, 

40,  41,  42 
examination   by,   37,   38,   39, 

40,  41,  42 

Observer,    18,   19,  20,  21 
Opacities,     cholesterin     crystals, 

139 

corneal,  128,  129,  130,  138 
fixed,  139 
floating,  139 
hemorrhages,   157 
in  aqueous,    138 
lenticular,  138 
locating  the  position  of,  138, 

139 

vitreous,  137,  139 
Opaque     nerve-fibers,     106,     107 

(Plate   IX.) 
Ophthalmoscope,  I 
choice  of  an,  I 
Helmholtz,    I 
how   to   use   the,   9,   10,   23, 

24,  25 

Loring,  2,  3,  6 
Morton,  2 
selection  of,  I 
Thorner,  8,  9 
Ophthalmoscopic       examination, 

23    (Chapter  I.) 
direct  method,  23,  26,  27,  28 
indirect  method,  26,  29,  30, 

3i 

Optic  atrophy,  primary,  246,  247 
(Plates  IX.  and  X.) 

secondary,    255 

simple,  255 
Optic  disc  (disk),  in,  112 

atrophic  cup,  233 

atrophy  of   (Plate  X.) 

coloboma   of,    105 

color  of,   112,    121,   229,  230 

congenital  crescent  of,  116 


294 


INDEX. 


Optic  disc,  connective  tissue  on, 

107,  112 
cupping    of,    231,    232,    233, 

234,   235 

detailed  study  of,  112 
elevation  of,  235,  236,  237 
enlargement  of,   237 
excavation  of  in  atrophy,  233 
hyperemia  of,  230 
in  glaucoma,  233,  234,  235 
level  of,  231,   232 
margin  of,  112 
myopic  crescent  of,  116,  118, 

271 
nerve  fibers,  106,  107  (Plate 

IX.) 

physiologic  cup,   113,   114 
pigment  on,  112 
pillar  of,  230,  231    ' 
shape  of,  112,  113 
situation   of,    112 
size  of,   in 
swelling,    estimating    extent 

of,  237 
Optic   nerve,   atrophy  of    (Plate 

X.) 

diseases  of  (Chapter  IX.) 
head  of,  in 

Optic  neuritis,   17,   18,   235 
retrobulbar,  244,  245 


Panophthalmitis,  272,  273 

cause  of,  272,  273 

prognosis  of,  273 

treatment  of,  273 
Papilla,    in,    112 
Papillitis,  235,  236,  237,  238,  239 

cause  of,  241,  242,  243 

prognosis,   2Ai 

treatment,  243 
Papillomacular  fibers,  245 


Papillo-retinitis,  193,  194,  238 
Parallactic    movement    (Chapter 

IV.) 

Parallax  (Chapter  IV.),  115 
Pencil,  48 

Perforation,  central  in  mirror,  2 
Perimetry,  140,  142,  143,  144,  145, 

146 

Perivasculits,    152 
Pernicious  anemia,  167 
Persistent    hyaloid    artery,    105. 

106 

Phthisis  bulbi,  273 
Physiologic  cup,  113,  114  (Chap- 
ter IV.)   232,  233 
estimation  of  depth  of,   114, 

115 

to    distinguish    from    patho- 
logic  cup,   233 
Pigment  on  disc,   120,   121 
ring,    1 20,   121 
streaks  in  retina,  228 
Pigmentary       degeneration       of 

retina,    211 

unusual  form  (Plate  VII.) 
Pigmentation  of  the  choroid,  126, 

260 
Pigmentosa,     retinitis,    211,    212 

(Plate  VII.) 
Plane  mirror,   12 

reflection  from,  51,  52 
Porus  opticus,  113 
Position   of   light,   21,   22 
of  observer,  20,  21,  22 
of  patient,  22,  23 
Posterior  polar  cataract,  102,  103 
staphyloma,   267 
synechia,   131 
Postpapillitic      atrophy       (Plate 

IX.) 

Primary    atrophy    of    the    optic 
nerve  (Plate  X.) 


INDEX. 


295 


Prisms,  58,  59 
Proliferating  retinitis,  153 
Pseudo-glioma,  226 
Pulsation,  arterial,  154 

venous,  123,  124,  154  (Chap- 
ter  IV.) 
Punctate   condition   of   the    fun- 

dus,   184,   185 

Pupil,  black  appearance  of,  9 
congenital  anomaly,  100,  101. 

102 
in    atrophy    of    optic    nerve, 

252 

reflex  from,  9 

Papillary  membrane,  101,  102 
Purulent    choroiditis,    262 

R 

Randall,  Dr.  B.  A.,  140 

Ray,  45 

Rays  of  light,  12 

convergent,  12,  47,  48 

divergent,  12,  47 

emergent,  45,  46 

incident,  45 

parallel,    12,  47 

reflected,    12 
Reflection,   12,  49,  50 

laws    of,    50 
Reflex,  corneal,  126 

chcfroidal,  26 

fundus,  26,   109 

red,   26,    109 

Weiss,    125 

Refraction,  57,  58,  59,  60,  61,  62 
Retina,  90,   124 

anatomy  of,  90,  91,  92 

anemia  of,   161 

atrophy   of,   271 

changes    in    vascularity    of, 
157,   158 

commotio,  224 


Retina,    detachment    of     (Plate 
VIII.),   219,   220,   221 
causes  of,  221 
diagnosis,  219,  220,  221, 

222 

prognosis,  223 
treatment,  223,  224 

diseases  of  (Chapter  VIII.) 

edema  of,   180 

exudation  into,  181 

glioma  of,  224,  225,  226 
diagnosis  of,  226 
prognosis  of,  226 
treatment,  226 

hemorrhages   into,    154,    155, 
156,  157,  158,  186 

hyperemia  of,  158,  159,  160 

inflammation  of,  176,  177 

irritation  of,  160,  161 

opacities    of,    178,    179,    180, 
181 

pigment  streaks  in,  228 

pigmentary  degeneration  of, 
214 

pigmentation  of,  158 

rupture  of,  224 

sclerosis  of,  214 

shot  or  watered  silk  appear- 
ance of,  125 

transparency  of,   125 

vessels  of,  125 
Retinal    atrophy,    271 

capillaries  of,   123,   124 

changes  due  to  intense  light, 
160,  161 

circulation  of,  125 

reflex,  109,  125 

veins,  thrombosis  of,  170,  171 

vessels,    123,    124,    125,    148, 
149,  150,  151,  152,  153, 

154 
diameter  of,  149,  150 


296 


INDEX. 


Retinal  vessels,  diseases  of,  149, 
150,  151 

distribution  of,  121,  122, 
123,   124 

light  streak  of,  122 

pulsation  of,   123,    124 

relative  size  of  arteries, 
and  veins,  148 

sclerosis  of,  149,  150,  151 

tortuosity        of        (See 
Thrombosis) 

walls   of,   151 
Retinitis,  176,  177 

albuminuric,     193,     194,    195 
causes  of,  178 
centralis  et  striata,  228 
circinata,  226,  227 
circumscribed,   184 
diagnosis  of,  177 
prognosis  of,  177,  178 
treatment,  178 

(Plate  IV.) 

varieties  of,   196 
degenerative,  196 
diabetica,  206 
diffuse,   182,   183 
electric,   160,   161 
hemorrhagic,  187,  196 

causes,   187 

prognosis,   187 

treatment,  188 
leukemic,  188,  189 
neuro-,  196 

of  pregnancy  (Plate  V.),  196 
pigmentosa,  2ii  (Plate  VII.) 

diagnosis  of,  214 

treatment   of,   214 
proliferans,    153 
punctata,   184,   185 
purulent,  228 
secondary,    187,   196 
serous,  182,  183 


Retinitis,  simple,  182,  183 

solar,  160,  161 

splenic,   188,   189 
treatment,  193 

syphilitic,   188 

treatment,   188 

varieties  of   (Chapter  VII.) 
Retinochoroiditis  (Plate  XI.) 
Retinoscopy,  76,  77,  78 

in  astigmatism,  77 

in  hypermetropia,  77 

in  myopia,  77 

methods  of  examination,  76 

77 

mirror,  76 
principle  of,  76 
Retrobulbar  neuritis,   244 
acute,  244,   245 
cause,  245 
prognosis,  245 
treatment,    245 
chronic,  244,  245 
cause,  245,  246 
prognosis,    246 
treatment,  246 
Ring,  choroidal,  116,  117 
pigment,    116,    117 
scleral,    116 
Room,  9,  10 
Rupture  of  the  choroid,  273,  27^ 


Sarcoma,  of  the  choroid,  274 

stages  of,  275 
Schematic  eye,  Thorington's,  14 

15 

Scleral  ring,  116 
Sclerophthalmia,  99 
Sclerosis    of    the    vessel    walls 

151,  152 

Sclera,   79,   80,   81 
Sclerotic,  79 


INDEX. 


297 


Scleral  ring,  115,  116 

Scotoma,   146,   147 

Secondary  atrophy  of  the  optic 

nerve,  255 
Selection  of  an  ophthalmoscope, 

i 
Senile  cataract,  102,  134 

changes  in  the  blood-vessels, 

iSi,  J52 

choroiditis,  270 

guttate  choroiditis,  270 
Serous  retinitis,  182,  183 
Shadow-test,  76,  77,  78 
Sight-hole,  2 

Simple    hypermetropic    astigma- 
tism, 75 

myopic  astigmatism,  75 
Snow  blindness,  160,  161 
Sparkling  synchysis,  139 
Spheres,  59,  60,  61,  62,  63 
Spherocylinders,  70 
Spiller,  Dr.  Wm.  G.,  248 
Squint,  22 

Staphyloma  posticum,  267 
Subhyaloid  hemorrhage,  157 
Subretinal  cysticercus,  139 
Sweet,  Dr.  W.  M.,  233 
Symmetric     coloboma     of     the 
lenses,  105 

dislocation  of  the  lenses,  105 
Synechia,  anterior,  131 

posterior,  131 
Synchysis   scintillans,    139 
Syphilitic     choroido-retinitis 
(Plate  XI.) 

retinitis,  188 


Tay,  227 

Test  cards,  140,  141,  142 
Thrombosis  of  the  central  artery, 
164 


Thrombosis,  of  retinal  vein,  170, 

171   (Plate  III.) 
causes  of,   175 
diagnosis,  174,   175 
treatment,  175 
Tiger-skin  fundus,  127 
Tilting  mirror,  2 
Tobacco  amblyopia,  245,  246 
Tortuosity  of  retinal  vessels,  170, 

171 

Toxic  amblyopia,  245,  246 
Tubercle  of  the  choroid,  275 
Tumor,  brain,  242 
Tumors,  intraocular,  274 

u 

Uvea,  oo 
Uveal  tract,  90 

V 

Vein,  central,  122 

decrease  in  size  of,  150 

increase  in  size  of,  149,  150 
Veins,  thrombosis,  170 

vorticose,  86 

Venous  pulsation,   123,   124 
Vessel   walls,    sclerosis    of,    151, 
152 

choroidal,   127 

cilioretinal,  124 

diseases  of,  151,  152 

new-formed  in  retina,  152 
in  vitreous,  153 
on  disc,  122 

retinal,  121,  122,  123,  124 

size  of,  28,  122 
Vision,  140,  141,  142 

central,  141,  142 

peripheral,  142,  143,  144,  145, 

146 

Visual  acuity   (Chapter  VI.) 
Vitreous,  94,  95,  136,  137 


298 


INDEX. 


Vitreous,  anatomy  of,  94,  95 
changes  in  choroiditis,  271 
cholesterin  crystals  in,  139 
diffuse  opacity  in,  272 
foreign  substances  in,  139 
hemorrhage  into,   136 
movable  opacity  in,  137,  138 
new  vessels  in,  153 
oblique   illumination  of,    137 
opacities,  136 

ophthalmoscopic       examina- 
tion of,    136,   137 
purulent   exudations    in,  272 

Vorticose  veins,  86 


w 

Walls  of  retinal  vessels,  151 

white   lines   along,   152 
Weeks,  Dr.  John  E.,  241 
Weiss  reflex,  125 
Welsbach,  u 
Wickerkiewicz,  101 


Yellow,  reflex  of  purulent  cho- 
roiditis,  272 
spot,   125 

position  of,   126 


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